Comprehensive Physiology Wiley Online Library

The Gastrointestinal Tract

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 Salivary Glands
2 Stomach
2.1 Gastric Secretion
3 Small Intestine
3.1 Morphology
3.2 Brush Border Membranes
3.3 Enzymes
3.4 Intestinal Permeability
3.5 Protein Synthesis
3.6 Intestinal Absorption
4 Gut‐Associated Immune System
5 Splanchnic Blood Flow
6 Gastrointestinal Motility
6.1 Esophagus
6.2 Stomach
6.3 Neuromuscular Functioning
6.4 Colon and Rectum
7 Pancreas
8 Liver and Biliary Tree
8.1 Morphology
8.2 Age‐Associated Effects
8.3 Consequences of Aging
8.4 Bile
9 Gastrointestinal Hormones
10 Cellular Proliferation
10.1 Esophagus and Stomach
10.2 Small Intestine
10.3 Colon
10.4 Effects of Caloric Restriction
Figure 1. Figure 1.

Effect of calcium diet in young and old subjects. Each subject was studied twice, once on the low‐calcium diet and once on the high‐calcium diet. P values are by paired analysis.

Reprinted from Ireland and Fortran 214 with permission
Figure 2. Figure 2.

Relation between age and hepatic secretion of cholesterol (n = 22), total bile acid synthesis (n = 18), and size of cholic acid pool (n = 18). Open circles denote women and closed circles men. To convert values for bile acids and cholesterol to milligrams, multiply by 400 and 0.39, respectively.

Reprinted from Einarsson et al. 115 with permission


Figure 1.

Effect of calcium diet in young and old subjects. Each subject was studied twice, once on the low‐calcium diet and once on the high‐calcium diet. P values are by paired analysis.

Reprinted from Ireland and Fortran 214 with permission


Figure 2.

Relation between age and hepatic secretion of cholesterol (n = 22), total bile acid synthesis (n = 18), and size of cholic acid pool (n = 18). Open circles denote women and closed circles men. To convert values for bile acids and cholesterol to milligrams, multiply by 400 and 0.39, respectively.

Reprinted from Einarsson et al. 115 with permission
References
 1. Abrams, C. K., M. Hamosh, S. K. Dutta, S. Van Hubbard, and P. Hamosh. Role of nonpancreatic lipolytic activity in exocrine pancreatic insufficiency. Gastroenterology 92: 125–129, 1987.
 2. Adam, R., I. Astarcioglu, D. Azoulay, M. Morino, Y. M. Bao, D. Castaing, and H. Bismuth. Age greater than 50 years is not a contraindication for liver donation. Transplant. Proc. 23: 2602–2603, 1991.
 3. Ajitsu, S., S. Mirabella, and H. Kawanishi. In vivo immunologic intervention in age‐related T cell defects in murine gut‐associated lymphoid tissues by IL2. Mech. Ageing Dev. 54: 163–183, 1990.
 4. Alison, M. R. Regulation of hepatic growth. Physiol. Rev. 66: 499–541, 1986.
 5. Ames, B. N., and L. S. Gold. Endogenous mutagens and the causes of aging and cancer. Mutat. Res. 250: 3–16, 1991.
 6. Ammann, R. Zur vaskularen Genese der chronischen pankreatitis. Dtsch. Med. Wochenschr. 101: 867–868, 1976.
 7. Ammann, R., and H. Sulser. Die senile chonische Pankreatitis‐eine neue nosologische einheit? Schweiz. Med. Wochenschr. 106: 429–437, 1976.
 8. Andersson, H., I. Bosaeus, T. Falkheden, and M. Melkersson. Transit time in constipated geriatric patients during treatment with a bulk laxative and bran: a comparison. Scand. J. Gastroenterol. 14: 821–826, 1979.
 9. Andrew, W. Senile changes in the pancreas of Wistar Institute rats and of man with special regard to the similarity of locule and cavity formation. Am. J. Anat. 74: 97–127, 1944.
 10. Andrew, W. Age changes in the parotid glands of Wistar Institute rats with special reference to the occurrence of oncocytes in senility. Am. J. Anat. 85: 157–197, 1949.
 11. Andrew, W., and N. V. Andrew. An age involution in the small intestine of the mouse. J. Gerontol. 12: 136–149, 1957.
 12. Andrews, G. R., B. Haneman, J. Arnold, J. C. Booth, and K. Taylor. Atrophic gastritis in the aged. Aust. Ann. Med. 16: 230–235, 1967.
 13. Angelin, B., and K. Einarsson. Influence of age on biliary lipid metabolism in man. In: Aging in Liver and Gastrointestinal Tract edited by L. Bianchi, P. R. Holt, O. F. W. James, and R. N. Butler. Lancaster, UK: MTP Press, Falk Symposium 47, Titisee, 1987, p. 161–168.
 14. Anisimov, V. N. Carcinogenesis and Aging, Boca Raton, FL: CRC Press, 1987, vols. 1, 2.
 15. Anuras, S., and J. Sutherland. Small intestinal manometry in healthy elderly subjects. J. Am. Geriatr. Soc. 32: 581–583, 1984.
 16. Aoyama, S., S. Kawamura, K. Nishio, K. Harima, T. Aibe, and T. Takemoto. Histopathological study on aging of the pancreas from 423 autopsy cases. Nippon Ronen Igakkai Zasshi 6: 574–579, 1979.
 17. Armbrecht, H. J., Changes in the components of the intestinal calcium transport system with age. In: Aging in Liver and Gastrointestinal Tract, edited by L. Bianchi. Lancaster, UK: MTP Press, 1988, p. 131–138.
 18. Armbrecht, H. J. Effect of age on calcium and phosphate absorption. Role of 1,25‐dihydroxyvitamin D. Miner. Electrolyte Metab. 16: 159–166, 1990.
 19. Armbrecht, H. J., W. G. Doubek, and S. B. Porter. Calcium transport by basal lateral membrane vesicles from rat small intestine decreases with age. Biochim. Biophys. Acta. 944: 367–373, 1988.
 20. Armbrecht, H. J., T. V. Zenser, M. E. H. Bruns, and B. B. Davis. Effect of age on intestinal calcium absorption and adaptation to dietary calcium. Am. J. Physiol. 236 (Endocrinol. Metab. Gastrointest. Physiol. 5): E769–E774, 1979.
 21. Armbrecht, H. J., T. V. Zenser, C. J. Gross, and B. B. Davis. Adaptation to dietary calcium and phosphorus restriction changes with age in the rat. Am. J. Physiol. 239 (Endocrinol. Metab. 2): E322–327, 1980.
 22. Arora, S., S. Hassarjian, S. D. Krasinski, B. Croffey, M. M. Kaplan, and R. M. Russell. Effect of age on tests of intestinal and hepatic function in healthy humans. Gastroenterology 96: 1560–1565, 1989.
 23. Arranz, E., S. O'Mahony, J. R. Barton, and A. Ferguson. Immunosenescence and mucosal immunity: significant effects of old age on secretory IgA concentrations and intraepithelial lymphocyte counts. Gut 33: 882–886, 1992.
 24. Atillasoy, E., and P. R. Holt. Gastrointestinal proliferation and aging. J. Gerontol. 48: B43–B49, 1993.
 25. Avioli, L. V., J. E. McDonald, and S. W. Lee. The influence of age on the intestinal absorption of 47Ca in women and its relation to 47Ca absorption in post‐menopausal osteoporosis. J. Clin. Invest. 44: 1960–1967, 1965.
 26. Axelson, J., P. Person, R. Gagnermo‐Persson, and R. K'kanson. Importance of the stomach in maintaining calcium homeostasis in the rat. Gut 32: 1298–1302, 1991.
 27. Babad, H., R. Ben‐Zvi, A. Bdolah, and M. Schramm. The mechanism of enzyme secretion by the cell. 4. Effects of inducers, substrates and inhibitors on amylase secretion by rat parotid slices. Eur. J. Biochem. 1: 96–101, 1967.
 28. Bailey, L. B., J. J. Cerda, B. S. Bloch, M. J. Bushby, L. Vargas, C. J. Chandler, and C. H. Halstead. Effect of age on poly‐ and monoglutamyl folacin absorption in human subjects. J. Nutr. 114: 1770–1776, 1984.
 29. Bailey, L. B., P. A. Wagner, G. J. Christakis, P. E. Araujo, H. Appledorf, C. G. David, E. Dorsey, and J. S. Dinning. Vitamin B12 status of elderly persons from urban low‐income households. J. Am. Geriatr. Soc. 28: 276–278, 1980.
 30. Baker, D. M., and R. M. Santer. A quantitative study of the effects of age on the noradrenergic innervation of Auerbach's plexus in the rat. Mech. Ageing Dev. 42: 147–158, 1988.
 31. Baker, D. M., S. P. Watson, and R. M. Santer. Evidence for a decrease in sympathetic control of intestinal function in the aged rat. Neurobiol. Aging 12: 363–365, 1991.
 32. Baker, H., S. P. Jaslow, and O. Frank. Severe impairment of dietary folate utilization in the elderly. J. Am. Geriatr. Soc. 26: 218–221, 1978.
 33. Baker, S. J., V. I. Mathan, and V. Cherian. The nature of the villi in the small intestine of the rat. Lancet i: 860, 1963.
 34. Bannister, J. J., L. Abouzekry, and N. W. Read. Effect of aging on anorectal function. Gut 28: 353–357, 1987.
 35. Barragry, J. M., M. W. France, D. Corless, S. P. Gupta, S. Switala, B. J. Boucher, and R. D. Cohen. Intestinal cholecalciferol absorption in the elderly and in younger adults. Clin. Sci. Mol. Med. 55: 213–220, 1978.
 36. Bartolo, D. C. C., J. A. Jarratt, and N. W. Read. The use of conventional electromyography to assess external sphincter neuropathy in man. J. Neurol. Neurosurg. Psychiatry 46: 1115–1118, 1983.
 37. Bartos, V., and J. Groh. The effect of repeated stimulation of the pancreas on the pancreatic secretion in young and aged men. Gerontol. Clin. 11: 56–62, 1969.
 38. Barz, H., K. D. Kunze, K. Voss, and H. Simon. Image processing in pathology. IV. Age dependent changes of morphometric features of liver cell nuclei in biopsies. Exp. Pathol. 14: 55–64, 1977.
 39. Baum, B. Evaluation of stimulated parotid saliva flow rate in different age groups. J. Dent. Res. 60: 1292–1296, 1981.
 40. Baum, B. J., E. E. Kousvelari, and F. G. Oppenheim. Exocrine protein secretion from human parotid glands during aging: stable release of the acidic prolinerich proteins. J. Gerontol. 37: 392–395, 1982.
 41. Baum, B. J., R. L. Levine, B. L. Kuyatt, and D. B. Sogin. Rat parotid gland amylase: evidence for alterations in an exocrine protein with increased age. Mech. Ageing Dev. 19: 27–35, 1982.
 42. Becker, G. H., J. Meyer, and H. Necheles. Fat absorption in young and old age. Gastroenterology 14: 80–92, 1950.
 43. Bender, A. D. Effect of age on intestinal absorption: implication for drug absorption in the elderly. J. Am. Geriatr. Soc. 16: 1331–1339, 1968.
 44. Berger, D., R. Crowther, J. C. Floyd, Jr., S. Pek, and S. S. Fajans. Effects of age on fasting levels of pancreatic hormones in healthy subjects. Diabetes 26: 381a, 1977.
 45. Berthelemy, P., M. Bouisson, B. Vellas, J. Moreau, N. Vaysse, J. L. Albarede, and A. Ribet. Postprandial cholecystokinin secretion in elderly with protein‐energy undernutrition. J. Am. Geriatr. Soc. 40: 365–369, 1992.
 46. Beumont, D. M., I. Cobden, W. L. Sheldon, M. F. Laker, O. F. W. James. Passive and active carbohydrate absorption by the ageing gut. Age Ageing 16: 294–300, 1987.
 47. Beyer, H. S., M. Ellefson, R. Sherman, and L. Zieve. Aging alters ornithine decarboxylase and decreases polyamines in regenerating rat liver but putrescine replacement has no effect. J. Lab. Clin. Med. 119: 38–47, 1992.
 48. Beyer, H. S., R. Sherman, and L. Zieve. Aging is associated with reduced liver regeneration and diminished thymidine kinase mRNA content and enzyme activity in the rat. J. Lab. Clin. Med. 118: 101–108, 1991.
 49. Bhanthumnavin, K., J. R. Wright, and C. H. Halsted. Intestinal transport of tritiated folic acid (3H‐PGA) in the everted gut sac of different aged rats. Johns Hopkins Med. J. 135: 152, 1974.
 50. Black, D. A., and I. S. Menzies. Intestinal absorption and renal clearance of sugar markers in the elderly. Br. Geriatr. Soc. Spring meeting, 1987.
 51. Bland, G., A. Banks, M. Nicholson, and A. L. Jones. Decreased liver DNA synthesis in old rats following partial hepatectomy is restored by epidermal growth factor. In: Liver and Aging, edited by K. Kitani. Amsterdam: Elsevier, 1991, p. 279–290.
 52. Bloomfield, A. L., and C. S. Keefer. Gastric acidity: relation to various factors such as age and physical fitness. J. Clin. Invest. 5: 205–227, 1928.
 53. Bodner, L., and B. J. Baum. Characteristics of stimulated parotid gland secretion in the aging rat. Mech. Ageing Dev. 31: 337–342, 1985.
 54. Bogart, B. I. The effect of aging on the histochemistry of the rat submandibular gland. J. Gerontol. 22: 372–375, 1967.
 55. Bogart, B. I. The effect of aging on the rat submandibular gland: an ultrastructural, cytochemical and biochemical study. J. Morphol. 130: 337–351, 1970.
 56. Bogdonoff, M. D., N. W. Shock, and M. P. Nichols. Calcium, phosphorus, nitrogen and potassium balance studies in the aged male. J. Gerontol. 8: 272–288, 1953.
 57. Bortolotti, M., G. Fradà, P. Vezzadini, G. Bonora, G. Barbagallo‐Sangiorgi, and G. Labò. Influence of gastric acid secretion on interdigestive gastric motor activity and serum motilin in the elderly. Digestion 38: 226–233, 1987.
 58. Bortolotti, M., G. J. R. Fradà, G. Barbagallo‐Sangiorgi, and G. Labò. Interdigestive gastroduodenal motor activity in the elderly. Gut 25: A1320, 1984.
 59. Boyd, E. Normal variability of the adult human liver and spleen. Arch. Pathol. 16: 350–372, 1933.
 60. Boyden, E. A., and S. A. Grantham. Evacuation of the gallbladder in old age. Surg. Gynecol. Obstet. 62: 34–42, 1926.
 61. Braaten, B., and M. Donowitz. Stimulated active CL secretion is decreased in descending colon of aged rabbits. Gastroenterology 88: A1333, 1985.
 62. Brasitus, T. A., K.‐Y. Yeh, P. R. Holt, and D. Schacter. Lipid fluidity and composition of intestinal microvillus membranes isolated from rats of different ages. Biochim. Biophys. Acta. 778: 341–348, 1984.
 63. Brauer, P. M., J. L. Slavin, and J. A. Marlett. Apparent digestibility of neutral detergent fiber in elderly and young adults. Am. J. Clin. Nutr. 34: 1061–1070, 1981.
 64. Bucher, N. L. R., M. N. Swaffield, and J. F. Ditroia. The influence of age upon the incorporation of thymidine‐2‐14C into DNA of regenerating rat liver. Cancer Res. 24: 509–512, 1964.
 65. Buchowski, M. S., and D. D. Miller. Lactose, calcium source and age affect calcium bioavailability in rats. J. Nutr. 121: 1746–1754, 1991.
 66. Bullamore, J. R., K. Wilkinson, J. C. Gallagher, B. E. C. Nordin, and D. H. Marshall. Effect of age on calcium absorption. Lancet ii: 535–537, 1970.
 67. Burkhardt, R., Iron overload of bone marrow and bone. In: Iron Metabolism and its Disorders, ICS 366, edited by H. Kief. Amsterdam: Excerpta Medica, 1975, p. 264–272.
 68. Butcher, F. R., J. A. Goldman, and M. Nemerovski. Effect of adrenergic agents on α‐amylase release and adenosine 3′, 5′‐monophosphate accumulation in rat parotid tissue slices. Biochim. Biophys. Acta. 392: 82–94, 1975.
 69. Butt, W., S. Kaufman, M. Wang, S. Cohen, and J. Ryan. Altered mechanical properties of the aged rat colon. Gastroenterology 98: A332, 1990.
 70. Calloway, N. O., C. F. Foley, and P. Langerbloom. Uncertainties in geriatric data. II. Organ size. J. Am. Geriatr. Soc. 13: 20–28, 1965.
 71. Cameron, A. J., and C. T. Lomboy. Barrett's esophagus: age, prevalence, and extent of columnar epithelium. Gastroenterology 103: 1241–1245, 1992.
 72. Carmel, R., R. M. Sinow, M. E. Siegel, and I. N. Samloff. Food cobalamin malabsorption occurs frequently in patients with unexplained low serum cobalamin levels. Arch. Intern. Med. 148: 1715–1719, 1988.
 73. Castlemen, C. M., C. N. Volans, and K. Raymond. The effect of ageing on drug absorption from the gut. Age Ageing 6: 138–143, 1977.
 74. Chauncey, H. H., G. A. Borkan, A. H. Wayler, R. P. Feller, and K. K. Kapur. Parotid fluid composition in healthy aging males. Adv. Physiol. Sci. 28: 323–328, 1981.
 75. Chen, T. S., G. J. Currier, and C. L. Wabner. Intestinal transport during the life span of the mouse. J. Gerontol. 45: B129–B133, 1990.
 76. Cheng, A. H. R., A. Gomez, J. G. Bergan, T. C. Lee, F. Monckeberg, and C. O. Chichester. Comparative nitrogen balance study between young and aged adults using three levels of protein intake from a combination wheat‐soy‐milk mixture. Am. J. Clin. Nutr. 31: 12–22, 1978.
 77. Chilla, R., H. Niemann, C. Arglebe, and B. F. Domagk. Age‐dependent changes in the α‐isoamylase pattern of human and rat parotid glands. Otorhinolaryngol. Relat. Spec. 36: 372–382, 1974.
 78. Chin, K. N. Ultrastructure of Peyer's patches in the aged mouse. Acta Anat. 84: 523–533, 1973.
 79. Chinn, A. B., P. S. Lavik, and D. B. Cameron. Measurement of protein digestion and absorption in aged persons by a test meal of I131‐labeled protein. J. Gerontol. 11: 151–153, 1956.
 80. Chow, B. F., J. P. Gilbert, K. Okuda, and C. Rosenblum. The urinary excretion test for absorption of vitamin B12. I. Reproducibility of results and agewise variation. Am. J. Clin. Nutr. 4: 142–146, 1956.
 81. Clarke, R. M. The effect of growth and of fasting on the number of villi and crypts in the small intestine of the albino rat. J. Anat. 112: 27–33, 1972.
 82. Clarke, R. M. The effects of age on mucosal morphology and epithelial cell production in rat small intestine. J. Anat. 123: 805–811, 1977.
 83. Coghill, M. F. The significance of gastritis. Postgrad. Med. J. 36: 433, 1960.
 84. Cohn, S. M., K. A. Roth, E. H. Birkenmeier, and J. I. Gordon. Temporal and spatial patterns of transgene expression in aging adult mice provide insights about the origins, organization, and differentiation of the intestinal epithelium. Proc. Natl. Acad. Sci. U.S.A. 88: 1034–1038, 1991.
 85. Connell, A. M., C. Hilton, G. Irvine, J. E. Lennard‐Jones, and J. J. Misiewicz. Variations in bowel habits in two sample populations. Br. Med. J. ii: 1095–1099, 1965.
 86. Cook, I. J., M. Gabb, V. Panagopoulos, G. G. Jamieson, W. J. Dodds, J. Dent, and D. J. Shearman. Pharyngeal (Zenkers) diverticulum is a disorder of upper esophageal sphincter opening. Gastroenterology 103: 1229–1235, 1992.
 87. Cornes, J. S. Number, size, and distribution of Peyer's patches in the human small intestine. I. The effect of age on Peyer's patches. Gut 6: 230–233, 1965.
 88. Corraza, G. R., A. Strocchi, R. Rossi, D. Sirola, and G. Gasbarrini. Sorbitol malabsorption in normal volunteers and in patients with coeliac disease. Gut 29: 44–48, 1988.
 89. Correa, P., C. Cuello, D. Duque, L. C. Burbano, F. T. Garcia, O. Bolanos, C. Brown, and W. Haenszel. Gastric cancer in Columbia. III. Natural history of precursor lesions. J. Natl. Cancer Inst. 57: 1027–1035, 1976.
 90. Crooks, J., K. O'Malley, and L. H. Stevenson. Pharmacokinetics in the elderly. Clin. Pharmacokinet. 1: 280–296, 1976.
 91. Cryer, B., J. S. Redfern, M. Goldschmiedt, E. Lee, and M. Feldman. Effect of aging in gastric and duodenal mucosal prostaglandin concentrations in humans. Gastroenterology 102: 1118–1123, 1992.
 92. Csendes, A., E. Guiraldes, A. Bancalari, I. Braghetto, and M. Ayala. Relation of gastroesophageal sphincter pressure and esophageal contractile waves to age in man. Scand. J. Gastroent. 13: 443–447, 1978.
 93. Cullan, C. E., D. A. Crouse, and T. G. Sharp. Adaptive changes in intestinal cell proliferation studies in situ and in ectopic petal intestinal grafts in ageing mice. In: Mechanisms of Intestinal Adaptation, edited by J. W. L. Robinson, R. H. Dowling, and E. O. Riecken. Lancaster, UK: MTS Press, Falk Symposium 30, 1982, p. 29–46.
 94. Culpepper‐Morgan, J. A., P. R. Holt, and M. J. Kreek. Aging changes in colonic opiate receptors in the guinea pig. Gerontologist 27: 88a, 1987.
 95. Daniels, C. K., D. L. Schmucker, H. Bazin, and A. L. Jones. Immunoglobulin A receptor of rat small intestinal enterocytes in unaffected by aging. Gastroenterology 94: 1432–1440, 1988.
 96. Darmenton, P., F. Raul, M. Doffoel, and J. Y. Wessely. Age influence on sucrose hydrolysis and on monosaccharide absorption along the SI of rat. Mech. Ageing Dev. 50: 49–55, 1989.
 97. David, H., and P. Reinke. Liver morphology with aging. In: Aging in Liver and Gastrointestinal Tract, edited by L. Bianchi, P. R. Holt, O. F. W. James, and R. N. Butler. Lancaster, UK: MTP Press, Falk Symposium 47, Titisee, 1987, 1988, p. 143–159.
 98. Davies, W. T., J. R. Kirkpatrick, G. M. Owen, and R. Shield. Gastric emptying in atrophic gastritis and carcinoma of the stomach. Scand. J. Gastroenterol. 6: 297–301, 1971.
 99. Dedichen, L. Anacidity in old persons. Acta Med. Scand. 7: 345–350, 1924.
 100. Del Corral, A., and R. Carmel. Transfer of cobalamin from the cobalamin‐binding protein of egg yolk to R binder of human saliva and gastric juice. Gastroenterology 98: 1460–1466, 1990.
 101. Derventzi, A., S. I. S. Rattan, and B. F. C. Clark. Senescent human fibroblasts are more sensitive to the effects of a phorbol ester on macromolecular synthesis and growth characteristics. Biochem. Int. 27: 903–911, 1992.
 102. Deschner, E. E., and H. T. Lynch. The influence of age and genetic risk for colonic epithelial cell proliferation. Proc. Am. Assoc. Cancer Res. 28: 179, 1987.
 103. Devroede, G., S. Vobecky, S. Masse, et al. Ischaemic fecal incontinence and rectal angina. Gastroenterology 83: 970–980, 1982.
 104. Di Lorenzo, D., C. P. Dooley, and J. E. Valenzuela. Role of fasting gastrointestinal motility in the variability of gastrointestinal transit time assessed by hydrogen breath test. Gut 32: 1127–1130, 1991.
 105. Di Magno, E. P., and W. H. J. Summerskill. Relations between pancreatic enzyme output and malabsorption in severe pancreatic insufficiency. N. Engl. J. Med. 288: 813–815, 1977.
 106. Dooley, J. S., B. J. Potter, H. C. Thomas, et al. A comparative study of the biliary secretion of human dimeric and monomeric IgA in rat and man. Hepatology 2: 232–237, 1982.
 107. Doubek, W. G., and H. J. Armbrecht. Changes in intestinal glucose transport over the lifespan of the rat. Mech. Ageing Dev. 39: 91–102, 1987.
 108. Draper, H. H. Physiologic aspects of aging. I. Efficiency of absorption and phosphorylation of radiothiamine. Proc. Soc. Exp. Biol. Med. 97: 121–124, 1958.
 109. Dubick, M. A., P. R. Morrill, and A. P. N. Majumdar. Aging: effect of phorbol ester administration on pancreatic enzymes in rats. Gastroenterology 98: A–410, 1990.
 110. Dunlap, C. E., H. Mattox, J. B. Nelson, and D. O. Castell. Morphometric analysis of enteric neurons in small intestine of the Fischer rat across age. Gastroenterology 94: A107, 1988.
 111. Eastwood, H. D. H. Bowel transit studies in the elderly radioopaque markers in the investigation of constipation. Gerontol. Clin. 14: 154–159, 1972.
 112. Ebersole, J. L., D. J. Smith, and M. A. Taubman. Secretory immune responses in aging rats. 1. Immunoglobulin levels. Immunology 56: 345–350, 1985.
 113. Eckardt, V. F., and P. M. Lecompte. Esophageal ganglia and smooth muscle in the elderly. Dig. Dis. 23: 443–448, 1978.
 114. Ecknauer, R., T. Vadakel, and R. Wepler. Intestinal morphology and cell production rate in aging rats. J. Gerontol. 37: 151–155, 1982.
 115. Einarsson, K., K. Nilsell, B. Leijd, and B. Angelin. Influence of age on secretion of cholesterol and synthesis of bile acids by the liver. N. Engl. J. Med. 313: 277–282, 1985.
 116. Ekberg, O., and M. J. Feinberg. Altered swallowing function in elderly patients without dysphagia: radiologic findings in 56 cases. Am. J. Radiol. 156: 1181–1184, 1991.
 117. Elsborg, L. Reversible malabsorption of folic acid in the elderly with nutritional folate deficiency. Acta Haematol. 55: 140–147, 1976.
 118. Enesco, H. E., I. Shimokawa, and B. P. Yu. Effect of dietary restriction and aging on polyploidy in rat liver. Mech. Ageing Dev. 59: 69–78, 1991.
 119. Ernst, D. N., W. O. Weigle, and M. L. Thoman. Retention of T cell reactivity to mitogens and alloantigens by Peyer's patch cells of aged mice. J. Immunol. 138: 26–31, 1987.
 120. Esposito, G., A. Faelli, M. Tosco, M. N. Orsenigo, and R. Battistessa. Age‐related changes in rat intestinal transport of D‐glucose, sodium, and water. Am. J. Physiol. 249 (Gastroin‐test. Liver Physiol. 12): G328–G334, 1985.
 121. Evans, M. A., E. J. Triggs, M. Cheung, G. A. Broe, and H. Creasey. Gastric emptying rate in the elderly: implications for drug therapy. J. Am. Geriatr. Soc. 29: 201–205, 1981.
 122. Evers, M. B., M. Isukura, D. H. Chung, D. Pardkh, K. Yoshinaga, G. H. Greeley, Jr., T. Uchida, C. M. Townsend, Jr., and J. C. Thompson. Neurotensin stimulates growth of colonic mucosa in young and aged rats. Gastroenterology 103: 86–91, 1992.
 123. Ewe, K., Permeation of macromolecules. In: Intestinal Absorption and Secretion, edited by E. Skadhauge and Y. Heintze. Lancaster, UK: MTP Press, 1984, p. S03–S04.
 124. Fausto, N. Protooncogenes and growth factors associated with normal and abnormal liver growth. Dig. Dis. Sci. 36: 653–658, 1991.
 125. Favus, M. J., D. J. Mangelsdorf, V. Tembe, B. J. Coe, and M. R. Haussler. Evidence for in vivo upregulation of the intestinal vitamin D receptor during dietary calcium restriction in the rat. J. Clin. Invest. 82: 218–224, 1988.
 126. Fehèr, E., and L. Penzes. Density of substance P, vasoactive intestinal polypeptide and somatostatin‐containing nerve fibers in the ageing small intestine of the rats. Gerontology 33: 341–348, 1987.
 127. Feibush, J. M., and P. R. Holt. Impaired absorptive capacity for carbohydrate in the aged. Dig. Dis. Sci. 27: 1095–1100, 1982.
 128. Ferraris, R. P., J. Hsiao, R. Hernandez, and B. Hirayama. Site density of mouse intestinal glucose transporters declines with age. Am. J. Physiol. 264 (Gastrointest. Liver Physiol. 27): G285–G293, 1993.
 129. Fich, A., M. Camilleri, and S. F. Phillips. Effect of age on human gastric and small bowel motility. J. Clin. Gastroenterol. 11: 416–420, 1989.
 130. Firky, M. E. Gastric secretory functions in the aged. Gerontol. Clin. 7: 216–226, 1965.
 131. Findor, J., V. Perez, I. E. Brush, M. Giovanetti, and N. Fiaravanti. Structure and ultrastructure of the liver in aged persons. Acta Hepato‐gastroenterol. 20: 200–204, 1973.
 132. Finkelstein, M. S., M. Ranner, and M. L. Greedman. Salivary and serum IgA levels in a geriatric outpatient population. J. Clin. Immunol. 4: 85–91, 1984.
 133. Firky, M. E. Exocrine pancreatic functions in the aged. J. Am. Geriatr. Soc. 16: 463–468, 1968.
 134. Fleming, B. B., and C. H. Barrows. The influence of aging on intestinal absorption of vitamin B12 of niacin in rats. Exp. Gerontol. 17: 121–126, 1982.
 135. Fox, P. C., M. W. Heft, M. Herrera, M. R. Bowers, I. D. Mandel, and B. J. Baum. Secretion of antimicrobial proteins from the parotid glands of different aged healthy persons. J. Gerontol. 42: 466–469, 1987.
 136. Frank, E. B., R. Lange, and R. W. McCallum. Abnormal gastric emptying in patients with atrophic gastritis with or without pernicious anemia. Gastroenterology 80: A1151, 1981.
 137. Freeman, H. J., and G. A. Quamme. Age‐related changes in sodium‐dependent glucose transport in rat small intestine. Am. J. Physiol. 251 (Gastrointest. Liver Physiol. 14): G208–G217, 1986.
 138. Freston, J. W., and E. Englert. The influence of age and excessive body weight on the distribution and metabolism of bromsulphalein. Clin. Sci. 33: 301–312, 1967.
 139. Fry, R. J. M., S. Lesher, and H. I. Kohn. Age effect on cell‐transit time in mouse jejunal epithelial cell. Am. J. Physiol. 201: 213–216, 1961.
 140. Fry, R. J. M., S. Lesher, and H. I. Kohn. Influence of age on the transit time of cells of the mouse intestinal epithelium. Lab. Invest. 11: 289–293, 1962.
 141. Fulp, S. R., C. B. Dalton, J. A. Castell, and D. O. Castell. Aging‐related alterations in human upper esophageal sphincter function. Am. J. Gastroenterol. 85: 1569–1572, 1990.
 142. Gabella, G. Fall in the number of myenteric neurons in aging guinea pigs. Gastroenterology 96: 1487–1493, 1989.
 143. Gallagher, J. C., B. L. Riggs, J. Eisman, A. Hamstra, S. B. Arnaud, and H. F. Deluca. Intestinal calcium absorption and serum vitamin D metabolites in normal subjects and osteoporotic patients. J. Clin. Invest. 54: 729–736, 1979.
 144. Gargouri, Y., H. Moreau, G. Pieroni, and R. Verger. Human gastric lipase: a sulfhydryl enzyme. J. Biol. Chem. 263: 2159–2162, 1988.
 145. Gargouri, Y., H. Moreau, and R. Verger. Gastric lipases: biochemical and physiological studies. Biochim. Biophys. Acta 1006: 255–271, 1989.
 146. Garlick, P. J., M. A. McNurlan, and V. R. Preedy. A rapid and convenient technique for measuring the rate of protein synthesis by injection of [3H] phenylalanine. Biochem. J. 192: 719–723, 1980.
 147. Gersovitz, M., H. N. Munro, J. Udall, and V. R. Young. Albumin synthesis in young and elderly subjects using a new stable isotope methodology: responses to level of protein intake. Metabolism 29: 1075–1086, 1980.
 148. Glass, G. B. J., A. A. Goldbloom, L. J. Boyd, R. Laughton, S. Rosen, and M. Rich. Intestinal absorption and hepatic uptake of radioactive vitamin B12 in various age groups and the effect of intrinsic factor preparations. Am. J. Clin. Nutr. 4: 124–133, 1956.
 149. Goldschmiedt, M., and M. Feldman. Age‐related changes in gastric acid secretion. In: Chronic Gastritis and Hypochlorhydria in the Elderly, edited by P. R. Holt and R. M. Russell. Boca Raton, FL: CRC Press, 1993. p. 13–30.
 150. Goldschmiedt, M., C. Barnett, B. E. Schwarz, W. E. Karnes, J. S. Redfern, and M. Feldman. Effect of age on gastric acid secretion and serum gastrin concentrations in healthy men and women. Gastroenterology 101: 977–990, 1991.
 151. Goldspink, D. F., S. E. M. Lewis, and F. J. Kelly. Protein synthesis during the developmental growth of the small and large intestine of the rat. Biochem. J. 217: 527–534.
 152. Goodman, S. A., and T. Makinodan. Effect of age on cell‐mediated immunity in long‐lived mice. Clin. Exp. Immunol. 19: 533–542, 1975.
 153. Gorbach, S. L., L. Nahas, P. I. Lerner, and L. Weinstein. Studies of intestinal microflora. Effects of diet, age, and periodic sampling on numbers of fecal microorganisms in man. Gastroenterology 53: 845–855, 1967.
 154. Goto, H., Y. Tsukamoto, M. Kuroiwa, A. Ohara, H. Hoshino, and K. Segawa. Effects of aging on gastric mucosal prostaglandins. Gastroenterology 100: A74, 1991.
 155. Greenberg, R. E., and P. R. Holt. Influence of aging upon pancreatic digestive enzymes. Dig. Dis. Sci. 31: 970–977, 1986.
 156. Greenberg, R. E., S. Bank, and V. Kranz. Effect of aging on aspirin induced inhibition of gastric mucosal prostaglandins. Gastroenterology 96: A183, 1989.
 157. Greenberg, R. E., N. Colman, and P. R. Holt. Folate conjugase pteroylpolyglutamate hydrolase activity is not impaired in the aging rat. Gastroenterology 90: 1438, 1985.
 158. Greenberg, R. E., P. P. McCann, and P. R. Holt. Trophic responses of the pancreas differ in aging rats. Pancreas 3: 311–316, 1988.
 159. Grinstead, W. C., Y. Charles, C. Pak, and G. J. Krejs. Effect of 1,25‐dihydroxyvitamin D3 on calcium absorption in the colon of healthy humans. Am. J. Physiol. 247 (Gastrointest. Liver Physiol. 10): G189–G192, 1984.
 160. Gullo, L., P. Priori, C. Daniele, M. Ventrucci, G. Gasbarrini, and G. Labo. Exocrine pancreatic function in the elderly. Gastroenterology 29: 407–411, 1983.
 161. Haaijman, J. J., and W. Hijman. Influence of age on the immunological activity and capacity of the CBA mouse. Mech. Ageing Dev. 3: 375–398, 1978.
 162. Haaijman, J. J., H. R. E. Schuit, and W. Hijmans. Immunoglobulin‐containing cells in different lymphoid organs of the CBA mouse during its life‐span. Immunology 32: 427–434, 1977.
 163. Haboubi, N. Y., P. Hudson, Q. Rahman, G. S. Lee, and A. Ross. Small‐intestinal transit time in the elderly. Lancet i: 933, 1988.
 164. Halvorson, L., G. Dotevall, and A. Walan. Gastric emptying in patients with achlorhydria or hyposecretion of hydrochloric acid. Scand. J. Gastroenterol. 8: 395–399, 1973.
 165. Hamilton, E. Cell proliferation and ageing in mouse colon. I. Repopulation after repeated x‐ray injury in young and old mice. Cell Tiss. Kinet. 11: 423–431, 1978.
 166. Heaney, R. P., K. T. Smith, R. R. Recker, and S. M. Hinders. Meal effects on calcium absorption. Am. J. Clin. Nutr. 49: 372–474, 1989.
 167. Hellemans, J., E. Joopsten, Y. Ghoos, H. N. Carchon, G. Vantrappen, W. Pelemans, and P. Rutgeerts. Positive 14 CO2 bile and breath test in elderly people. Age Ageing 13: 138–143, 1984.
 168. Heller, T., P. R. Holt, and A. Richardson. Food restriction retards age‐related histological changes in rat small intestine. Gastroenterology 98: 387–391, 1990.
 169. Heller, T. D., P. R. Holt, and A. Richardson. Food restriction retards age‐related histologic changes in rat small intestine. Gastroenterology 98: 387–391, 1990.
 170. Von Hellthaler, G., H. Köhler, and W. Rotzsch. Alternsabhängige veränderungen der proteinsynthese von dündarmringen. Z. Alternsforsch. 24: 243–247, 1971.
 171. Hinsull, S. M. Effect of colloidal bismuth subcitrate on age related gastric lesions in the rat. Gut 32: 355–360, 1991.
 172. Hinton, J. M., J. E. Lennard‐Jones, and A. C. Young. A new method for studying gut transit times using radiopaque markers. Gut 10: 842–847, 1969.
 173. Hirschowitz, B. I., and A. Lanas. Effect of aging on gastric acid and pepsin secretion‐cross‐sectional studies in du and non‐du humans and longitudinal studies in fistula dogs. Gastroenterology 102: A83, 1992.
 174. Hodges, S. J., M. J. Pilkington, M. J. Shearer, L. Bitensky, and J. Chayen. Age‐related changes in the circulating levels of congeners of vitamin D2, menaquinone‐7 and menaquinone‐8. Clin. Sci. 78: 63–66, 1990.
 175. Höhn, P., H. Gabbert, and R. Wagner. Differentiation and aging of the rat intestinal mucosa. II. Morphological, enzyme histochemical and disc electrophoretic aspects of the aging of the small intestinal mucosa. Mech. Ageing Dev. 7: 217–226, 1978.
 176. Hollander, D., and V. D. Dadufalza. Aging: its influence on the intestinal unstirred water layer thickness. J. Physiol. Pharmacol. 61: 1501–1508, 1983.
 177. Hollander, D., and V. D. Dadufalza. Intestinal exsorption of oleic acid: influence of aging, bile, pH and ethanol. J. Nutr. 113: 511–518, 1983.
 178. Hollander, D., and V. D. Dadufalza. Aging associated pancreatic exocrine insufficiency in the unanesthetized rat. Gerontology 30: 218–222, 1984.
 179. Hollander, D., and V. D. Dadufalza. Lymphatic and portal absorption of vitamin E in aging rats. Dig. Dis. Sci. 34: 768–772, 1989.
 180. Hollander, E., and D. Morgan. Increase in cholesterol intestinal absorption with aging in the rat. Exp. Gerontol. 14: 201–204, 1979.
 181. Hollander, E., and D. Morgan. Aging: its influence on vitamin A intestinal absorption in vivo by rat. Exp. Gerontol. 14: 301–305, 1979.
 182. Hollander, D., and H. Tarnawski. Influence of aging on vitamin D absorption and unstirred water layer dimensions in the rat. J. Lab. Clin. Med. 103: 462–469, 1984.
 183. Hollander, D., and H. Tarnawski. Aging‐associated increase in intestinal absorption of macromolecules. Gerontology 31: 133–137, 1985.
 184. Hollander, D., and H. Tarnawski. Age‐associated increase in intestinal absorption of macromolecules. Gerontology 31: 133–137, 1985.
 185. Hollander, D., V. D. Dadufalza, and E. G. Sletten. Does essential fatty acid absorption change with aging? J. Lipid Res. 25: 129–134, 1984.
 186. Hollander, D., V. Dadufalza, R. Weindruch, and R. L. Walford. Influence of life‐prolonging dietary restriction on intestinal vitamin A absorption in mice. Age 9: 57–60, 1986.
 187. Hollander, D., A. Tarnawski, J. Stachura, and H. Gergely. Morphologic changes in gastric mucosa of aging rats. Dig. Dis. Sci. 34: 1692–1700, 1989.
 188. Hollis, J. B., and D. O. Castell. Esophageal function in elderly men. A new look at “presbyesophagus.” Ann. Intern. Med. 80: 371–374, 1974.
 189. Holt, P. R., The problem of fat in defined‐formula diets; pros and cons. In: Defined Formula Diets for Medical Purposes, edited by M. Shils. Chicago: American Medical Association, 1977, p. 34–38.
 190. Holt, P. R., Effects of aging upon intestinal absorption. In: Nutritional Approaches to Aging Research, edited by G. B. Moment. Boca Raton, FL: CRC Press, 1982, p. 157–177.
 191. Holt, P. R. Clinical significance of bacterial overgrowth in elderly people. Age Ageing 21: 1–4, 1992.
 192. Holt, P. R., and J. Balint. The effects of aging upon intestinal lipid absorption. Am. J. Physiol. 264 (Gastrointest. Liver Physiol. 27): G1–G6, 1993.
 193. Holt, P. R., and A. A. Dominguez. Intestinal absorption of triglyceride and vitamin D3 in aged and young rats. Dig. Dis. Sci. 26: 1109–1115, 1981.
 194. Holt, P. R., and R. N. Dubois. In vivo immediate early gene expression induced in intestinal and colonic mucosa by refeeding. FEBS Lett. 287: 102–104, 1991.
 195. Holt, P. R., and G. D. Luk. Aging intestinal polyamine metabolism in the rat. Exp. Gerontol. 25: 173–181, 1990.
 196. Holt, P. R., and K. Y. Yeh. Small intestinal crypt cell proliferation rates are increased in senescent rats. J. Gerontol. 44: B9–B14, 1988.
 197. Holt, P. R., and K. Y. Yeh. Colonic proliferation is increased in senescent rats. Gastroenterology 95: 1556–1563, 1988.
 198. Holt, P. R., and K.‐Y. Yeh. Aging and gastrin production: changes in serum and antral gastrin concentrations in the rat. J. Gerontol. 44: M62–M65, 1989.
 199. Holt, P. R., T. D. Heller, and A. G. Richardson. Food restriction retards age‐related biochemical changes in rat small intestine. J. Gerontol. 46: B89–B94, 1991.
 200. Holt, P. R., D. P. Kotler, and R. R. Pascal. A simple method for determining epithelial cell turnover in small intestine—studies in young and aging rat gut. Gastroenterology 84: 69–74, 1983.
 201. Holt, P. R., D. P. Kotler, and R. R. Pascal. Delayed enzyme expression: a defect of aging rat gut. Gastroenterology 89: 1026–1034, 1985.
 202. Holt, P. R., R. R. Pascal, and D. P. Kotler. Effect of aging upon small intestinal structure in the Fisher rat. J. Gerontol. 39: 642–647, 1984.
 203. Holt, P. R., A. R. Tierney, and D. P. Kotler. Delayed enzyme expression: a defect of aging rat gut. Gastroenterology 89: 1026–1034, 1985.
 204. Holt, P. R., K. Y. Yeh, and D. P. Kotler. Altered controls of proliferation in proximal small intestine of the senescent rat. Proc. Natl. Acad. Sci. U.S.A. 85: 2771–2775, 1988.
 205. Horowitz, M., G. J. Maddern, B. E. Chatterton, P. J. Collins, P. E. Harding, and D. J. C. Shearman. Changes in gastric emptying rates with age. Clin. Sci. 67: 213–218, 1984.
 206. Horowitz, M., J. Wishart, L. Mundy, and B. E. C. Nordin. Lactose and calcium absorption in postmenopausal osteoporosis. Arch. Intern. Med. 147: 524–536, 1987.
 207. Horst, R. L., J. P. Goff, and T. A. Reinhardt. Advancing age results in reduction of intestinal and bone 1,25‐dihydroxyvitamin D receptor. Endocrinology 126: 1053–1057, 1990.
 208. Houcke, E., M. Houcke, and J. Leblois. The pancreas of older adults: a histological study. Presse Med. 72: 1887–1892, 1964.
 209. Howell, T. H. Organ weights in nonagenarians. J. Am. Ger‐iatr. Soc. 26: 385–390, 1978.
 210. Hurdle, A. D. F., and T. C. Picton‐Williams. Folic‐acid deficiency in elderly patients admitted to hospital. Br. Med. J. ii: 202–205, 1966.
 211. Husebye, E., and K. Engedal. The patterns of motility are maintained in the human small intestine throughout the process of aging. Scand. J. Gastroenterol. 27: 397–404, 1992.
 212. Hyams, D. E. The absorption of vitamin B12 in the elderly. Gerontol. Clin. 6: 193–206, 1964.
 213. Ihre, T. Studies on anal function in continent and incontinent patients. Scand. J. Gastroenterol. 9 (suppl. 25): 1–64, 1974.
 214. Ireland, P., and J. S. Fordtran. Effect of dietary calcium and age on jejunal calcium absorption in humans studied by intestinal perfusion. J. Clin. Invest. 52: 2673–2681, 1973.
 215. Ishida, A., Y. Yoshikai, S. Murosaki, C. Kubo, Y. Kidaka, and K. Nomoto. Consumption of milk from cows immunized with intestinal bacteria influences age‐related changes in immune competence in mice. J. Nutr. 122: 1875–1883, 1992.
 216. Isukura, M., D. Parekh, B. M. Evers, K. Yoshinaga, G. H. Greeley, Jr., C. M. Townsend, Jr., and J. C. Thompson. Effect of aging on neurotensin‐stimulated intestinal growth in rats. Gastroenterology 98: A416, 1990.
 217. Ito, H., B. J. Baum, and G. S. Roth. (β‐Adrenergic regulation of rat parotid gland exocrine protein secretion during aging. Mech. Ageing Dev. 15: 177–188, 1981.
 218. Jacobs, A. M., and G. M. Owen. The effect of age on iron absorption. J. Gerontol. 24: 95–96, 1969.
 219. Jakab, L., and L. Penzes. Relationship between glucose absorption and villus height in aging. Experientia 37: 740–742, 1981.
 220. Joske, R. A., E. S. Finckh, and I. J. Wood. A study of 100 consecutive successful gastric biopsies. Q. J. Med. 24: 269–294, 1955.
 221. Jusko, W. L., G. Levy, and S. J. Yaffa. Effect of age on intestinal absorption of riboflavin in humans. J. Pharm. Sci. 59: 487–490, 1970.
 222. Kampmann, J. P., J. Sinding, and I. Moller‐Jorgensen. Effect of age on liver function. Geriatrics 30: 91–95, 1975.
 223. Karbach, U., and W. Rummel. Calcium transport across the colon ascendens and the influence of 1,25‐dihydroxyvitamin D3 and dexamethasone. Eur. J. Clin. Invest. 17: 368–374, 1987.
 224. Katelaris, P. H., F. Seow, B. P. C. Lin, et al. Effect of age, Helicobacter pylori infection, and gastritis with atrophy on serum gastrin and gastric acid secretion in healthy men. Gut 34: 1032–1037, 1993.
 225. Kataoka, S., and K.‐I. Syoji. Elevated cholecystokinin‐like activity in the duodenal mucosa in patients with cholecystolithiasis. Toboku J. Exp. Med. 145: 395–401, 1985.
 226. Kawanishi, H. and K. Joseph. Effects of phorbol myristate and ionomycin on in vitro growth of aged Peyer's patch T and B cells. Mech. Ageing Dev. 65: 289–300, 1992.
 227. Kawanishi, H., and J. Kiely. Immune‐related alterations in aged gut‐associated lymphoid tissues in mice. Dig. Dis. Sci. 34: 175–184, 1989.
 228. Kawanishi, H. H., S. Ajitsu, and S. Mirabella. Impaired humoral immune responses to mycobacterial antigen in aged murine gut‐associated lymphoid tissues. Mech. Ageing Dev. 54: 143–161, 1990.
 229. Kawanishi, H., S. Shigeru, and A. Shin. Aging‐associated intrinsic defects in IgA production by murine Peyer's patch B cell stimulated by autoreactive Peyer's patch T cell hybridoma‐derived B cell stimulatory factors (BSF). Mech. Ageing Dev. 49: 61–78, 1989.
 230. Kawano, S., H. Tanimura, N. Sato, K. Nagano, S. Tsuji, Y. Takei, M. Tsujii, N. Haashi, E. Masuda, T. Kashiwage, H. Fusamoto, and T. Kamada. Age‐related change in human gastric mucosal energy metabolism. Scand. J. Gastroenterol. 26: 701–706, 1991.
 231. Keane, P., D. Colwell, H. P. Baer, A. S. Clanachan, and G. W. Scott. Effects of age, gender and female sex hormones upon contractility of the human gallbladder in vitro. Surg. Gynecol. Obstet. 163: 555–560, 1986.
 232. Keelan, M., K. Walker, and A. B. R. Thomson. Intestinal morphology, marker enzymes and lipid content of brush border membranes from rabbit jejunum and ileum: effect of aging. Mech. Ageing Dev. 31: 49–68, 1985.
 233. Kekki, M., and P. Sipponen. Age behavior of gastric acid secretion in males and females with a normal antral and body mucosa. Scand. J. Gastroenterol. 18: 1009–1016, 1983.
 234. Kendall, M. J. The influence of age on the xylose absorption test. Gut 11: 498–501, 1970.
 235. Kesavan, V., and J. M. Noronha. Folate malabsorption in aged rats related to low levels of pancreatic folyl conjugase. Am. J. Clin. Nutr. 37: 262–267, 1983.
 236. Khalil, T., M. Fujimura, C. M. Towsend, G. H. Greely, and J. C. Thompson. Effect of aging on pancreatic secretion in rats. Am. J. Surg. 149: 120–125, 1985.
 237. Khalil, T., and J. C. Thompson. Aging and gut peptides. In: Gastrointestinal Endocrinology, edited by J. C. Thompson, C. H. Greeley, Jr., P. L. Rayford, and C. M. Townsend, Jr. New York: McGraw‐Hill, 1987, p. 147–157.
 238. Khalil, T., J. P. Walker, I. Wiener, et al. Effect of aging on gallbladder contraction and release of cholecystokinin‐33 in humans. Surgery 98: 423–429, 1985.
 239. Kim, S.‐K. Age‐related changes in the cellular level of amylase and protein synthesis in the rat parotid gland. J. Dent. Res. 60: 738–747, 1981.
 240. Kim, S. K., D. W. Calkins, P. A. Weinhold, and S. S. Han. Changes in the synthesis of exportable and non‐exportable proteins in parotid glands during aging. Mech. Ageing Dev. 18: 239–250, 1982.
 241. Kim, S. K., P. A. Weinhold, D. W. Calkins, and V. W. Hartog. Comparative studies of the age‐related changes in protein synthesis in the rat pancreas and parotid gland. Exp. Gerontol. 16: 91–99, 1981.
 242. Kim, S. K., P. A. Weinhold, S. S. Han, and D. J. Wagner. Age‐related decline in protein synthesis in the rat parotid gland. Exp. Gerontol. 15: 77–85, 1980.
 243. Kim, S. W., D. Parekh, C. M. Townsend, and J. C. Thompson. Effects of aging on duodenal bicarbonate secretion. Ann. Surg. 212: 332–338, 1990.
 244. Kirk, J. E., and M. Chieffi. Effect of oral thiamine administration on thiamine content of the stool. Proc. Soc. Exp. Biol. Med. 77: 464–466, 1951.
 245. Kitani, K., Bile acids in aging. In: Aging in Liver and Gastrointestinal Tract, edited by L. Bianchi, P. R. Holt, O. F. W. James, and R. N. Butler. Lancaster, UK: MTP Press, 1988, Falk Symposium 47, Titisee, 1987, p. 169–180.
 246. Klimas, J. E. Intestinal glucose absorption during the life‐span of a colony of rats. J. Gerontol. 23: 529–532, 1968.
 247. Knox, T. A., Z. Kassarjian, B. Dawson‐Hughes, B. B. Golner, G. E. Dallal, S. Arora, and R. M. Russell. Calcium absorption in elderly subjects on high‐ and low‐fiber diets: effect of gastric acidity. Am. J. Clin. Nutr. 53: 1480–1486, 1991.
 248. Koff, R. S., A. J. Garvey, S. W. Burney, and B. Bell. Absence of an age effect on sulphobromphthalein retention in healthy men. Gastroenterology 65: 300–302, 1973.
 249. Kogire, M., D. Parekh, J. Ishizuka, G. H. Greeley, Jr., C. M. Townsend, Jr., and J. C. Thompson. Effects of aging on gastrin and somatostatin secretion from the isolated perfused rat stomach. Dig. Dis. Sci. 38: 303–308, 1993.
 250. Korbuly, D. Note on the influence of age on sodium‐ and potassium‐absorption from the intestine of the rat. Gerontologia 12: 99–105, 1966.
 251. Kountz, W. B., L. Hofstater, and P. G. Ackermann. Nitrogen balance studies on elderly people. Geriatrics 2: 173–182, 1947.
 252. Krasinski, S. D., J. S. Cohn, E. J. Schaefer, and R. M. Russell. Postprandial plasma retinyl ester response is greater in older subjects compared with younger subjects. J. Clin. Invest. 85: 883–892, 1990.
 253. Krasinski, S. D., R. M. Russell, C. L. Otradove, J. A. Sadowski, S. C. Hartz, R. A. Jacob, and R. B. McGandy. Relationship of vitamin A and vitamin E intake to fasting plasma retinol, retinol binding protein, retinyl esters, carotene, α‐tocopherol and cholesterol among elderly and young adults: increased plasma retinyl esters among vitamin A supplement users. Am. J. Clin. Nutr. 49: 112–120, 1989.
 254. Kreel, L., and B. Sandin. Changes in pancreatic morphology associated with aging. Gut 14: 962–970, 1973.
 255. Kupfer, R. M., M. Heppell, J. W. Haggith, and D. N. Bateman. Gastric emptying and small‐bowel transit rate in the elderly. J. Am. Geriatr. Soc. 33: 340–343, 1985.
 256. La Brooy, J. S., P. J. Male, A. K. Beavis, and J. J. Misiewicz. Assessment of the reproducibility of the lactulose H2 breath test as a measure of mouth to caecum transit time. Gut 24: 893–896, 1983.
 257. Lans, J., R. Jaszeuski, F. Arlow, J. Juread, J. Glarian, G. D. Luk, and A. Majumdar. Supplemental calcium suppresses colonic mucosal odc activity in elderly pts with adenomatous polyps. Gastroenterology 98: A2902, 1990.
 258. Laster, L., and F. J. Ingelfinger. Intestinal absorption—aspects of structure, function and disease of the small‐intestine mucosa. N. Engl. J. Med. 264: 1138–1148, 1961.
 259. Laugier, R., and H. Sarles. The pancreas. In: Clinics in Gastroenterology, edited by O. F. W. James. London: Saunders, 1985, p. 749.
 260. Lee, M., and M. Feldman. Age‐related changes in gastric mucosal prostaglandin (PG) synthesis and aspirin‐induced injury in rats. Gastroenterology 102: A563, 1992.
 261. Lesher, S., R. J. M. FRY, and H. I. Kohn. Age and the generation time of the mouse duodenal epithelial cell. Exp. Cell Res. 24: 335–343, 1961.
 262. Lester, E., R. K. Skinner, and M. R. Willis. Seasonal variation in serum 25–hydroxyvitamin D concentrations in the elderly in Britain. Lancet i: 979–980, 1977.
 263. Bond, J. H. and M. D. Levitt. Use of pulmonary hydrogen (H2) measurements to quantitate carbohydrate absorption. J. Clin. Invest. 51: 1219–1225, 1972.
 264. Levitt, M. D., J. M. Kneip, and D. G. Levit. Use of laminar flow and unstirred layer models to predict intestinal absorption in the rat. J. Clin. Invest. 81: 1365–1369, 1988.
 265. Liang, C. T., J. Barnes, S. Takamoto, and B. Sacktor. Effect of age on calcium uptake in isolated duodenum cells. Role of 1,25 dihydroxyvitamin D3. Endocrinology 124: 2830–2836, 1989.
 266. Lin, C.‐F., and L. Hayton. Absorption of polyethylene glycol 400 administered orally to mature and senescent rats. Age 6: 52–56, 1981.
 267. Lin, C. F., and W. L. Hayton. GI motility and subepithelial blood flow in mature and senescent rats. Age 6: 46–51, 1983.
 268. Lindi, C., P. Marciani, A. Faelli, and G. Esposrro. Intestinal sugar transport during aging. Biochim. Biophys. Acta 816: 411–414, 1985.
 269. Lipkin, M. Phase 1 and phase 2 proliferative lesions of colonic epithelial cells in diseases leading to colonic cancer. Cancer 34: 878–888, 1974.
 270. Lutz, T., and E. Scharrer. Effect of short‐chain fatty acids on calcium absorption by the rat colon. Exp. Physiol. 76: 615–618, 1991.
 271. Maclaughlin, J., and M. F. Hollock. Aging decreases the capacity of human skin to produce vitamin D3. J. Clin. Invest. 76: 1536–1538, 1985.
 272. Maclennan, W. J., and J. C. Hamilton. Vitamin D supplements and 25‐hydroxyvitamin D concentration in the elderly. Br. Med. J. ii: 859–861, 1977.
 273. Madsen, J. L. Effects of gender, age, and body mass index on gastrointestinal transit times. Dig. Dis. Sci. 37: 1548–1553, 1992.
 274. Maitra, R. S., E. A. Edgerton, and A. P. Nandi Majumdar. Gastric secretion during aging in pyloric‐ligated rats and effects of pentagastrin. Exp. Gerontol. 23: 463–472, 1988.
 275. Majumdar, A. P. N. Regulation of gastric mucosal cell proliferation during advancing age. Facts Res. Gerontol. 2: 27–34, 1992.
 276. Majumdar, A. P. N., and M. A. Dubick. Gastrin affects enzyme activity and gene expression in the aging rat pancreas. Exp. Gerontol. 26: 57–64, 1991.
 277. Majumdar, A. P., E. A. Edgeron, Y. Dayal, and S. N. S. Murthy. Gastrin levels and trophic action during advancing age. Am. J. Physiol. (Gastrointest. Liver Physiol. 17): G538–G542, 1988.
 278. Majumdar, A. P. N., S. Jasti, J. S. Hatfield, J. Tureaud, and S. E. G. Fliegiel. Morphological and biochemical changes in gastric mucosa of aging rats. Dig. Dis. Sci. 35: 1364–1370, 1990.
 279. Majumdar, A. P. N., J. A. Moshier, F. L. Arlow, and G. D. Luk. Biochemical changes in the gastric mucosa after injury in young and aged rats. Biochim. Biophys. Acta 992: 35–40, 1989.
 280. Makinodan, T., and M. M. B. Kay. Age influence on the immune system. Adv. Immunol. 29: 287–330, 1990.
 281. Malamud, D. Amylase secretion from mouse parotid and pancreas the role of cyclic AMP and isoproterenol. Biochim. Biophys. Acta 279: 373–376, 1972.
 282. Marchesini, G., V. Bua, A. Brunori, G. Bianchi, P. Pisi, A. Fabbri, M. Zoli, and E. Pisi. Galactose elimination capacity and liver volume in aging man. Hepatology 8: 1079–1083, 1988.
 283. Marco, J., J. A. Hedo, and M. L. Villanueva. Hyperglucagonism in the elderly. Diabetes 26: 381a, 1977.
 284. Masoro, E. J. Food restriction in rodents: an evaluation of its role in aging. J. Gerontol. 43: B59–B64, 1988.
 285. Massey, B. T., S. Sonnenberg, and D. J. McCanty. Achalasia epidemiology and comorbidity in a geriatric population: an analysis of medicare data. Gastroenterology 98: A85, 1990.
 286. Matheson, D. M., and M. R. B. Keighley. Manometric evaluation of rectal prolapse and faecal incontinence. Gut 22: 126–129, 1981.
 287. Mathis, J. Beitrage zur konntris das fledermaus darmes. Z. Mikr‐anat. Forsch. 12: 595–647, 1928.
 288. Mayersohn, M. The xylose test to assess gastrointestinal absorption in the elderly: a pharmacokinetic evaluation of the literature. J. Gerontol. 37: 300–305, 1982.
 289. McDougal, J. W., M. S. Miller, and T. F. Burks. Intestinal transit and gastric emptying in young and senescent rats. Dig. Dis. Sci. 25: A–15, 1980.
 290. McEvoy, A., J. Dutton, and O. F. W. Jamems. Bacterial contamination of the small intestine is an important cause of occult malabsorption in the elderly. Br. Med. J. 287: 789–793, 1983.
 291. McMahon, T. F., W. P. Beierschmitt, and M. Weiner. Changes in phase I and phase II biotransformation with age in male Fischer 344 rat colon: relationship to colon carcinogenesis. Cancer Lett. 36: 273–282, 1987.
 292. Medvedev, Z. A. Age‐related polyploidization of hepatocytes: the cause and possible role. Exp. Gerontol. 21: 277–282, 1986.
 293. Melkersson, M., H. Anderson, I. Bosaeus, and T. Falkhenden. Intestinal transit time in constipated and non‐constipated geriatric patients. Scand. J. Gastroenterol. 18: 593–597, 1983.
 294. Mel Tune, J., D. P. McGinty, F. Navab, G. K. Patel, and Texter, E. C., Jr., The spectrum of mesenteric vascular insufficiency. In: The Aging Gut, Pathophysiology, Diagnosis, and Management, edited by E. C. Texter, Jr. New York: Masson, 1983, p. 105–115.
 295. Menzies, R. A., R. K. Mishra, and P. H. Gold. The turnover of ribosomes and soluble RNA in a variety of tissues of young adult and aged rats. Mech. Ageing Dev. 1: 117–132, 1972.
 296. Merry, B. J., E. M. Sheena, and D. F. Goldspink. The influence of age and chronic restricted feeding on protein synthesis in the small intestine of the rat. Exp. Gerontol. 27: 191–200, 1992.
 297. Meshkinpour, H., M. Smith, and D. Hollander. Influence of ageing on the surface area of the small intestine in the rat. Exp. Gerontol. 16: 399–404, 1981.
 298. Meyer, J., and H. Necheles. Studies in old age. IV. The clinical significance of salivary, gastric and pancreatic secretion in the aged. JAMA 115: 2050–2055, 1940.
 299. Mione, M. C., S. L. Erdo, B. Kiss, A. Ricci, and F. Amenta. Age‐related changes of noradrenergic innervation of rat splanchnic blood vessels: a histofluorescence and neurochemical study. J. Auton. Nerv. Sys. 25: 27–33, 1988.
 300. Miyasaka, K., and K. Kitani. Aging and pancreatic exocrine function: studies in conscious male rats. Pancreas 2: 523–530, 1987.
 301. Miyasaka, K., and K. Kitani. Aging and pancreatic exocrine function: studies in female conscious rats. Dig. Dis. Sci. 34: 841–848, 1989.
 302. Miyasaka, K., R. Nakamura, and K. Kitani. Effects of trypsin inhibitor (camostate) on pancreas and CCK release in young and old female rats. J. Gerontol. 44: M136–M140, 1989.
 303. Mobarhan, S., H. K. Seitz, R. M. Russell, R. Mehta, J. Hupert, H. Friedman, T. J. Layden, M. Meydani, and P. Langenberg. Age‐related effects of chronic ethanol intake on vitamin A status in Fisher 344 rats. J. Nutr. 121: 510–517, 1991.
 304. Mold, J. W., L. E. Reed, A. B. Davis, M. P. H. Melvin, L. Allen, D. L. Decktor, and M. Robinson. Prevalence of gastroesophageal reflux in elderly patients in a primary care setting. Am. J. Gastroenterol. 86: 965–970, 1991.
 305. Montgomery, R. D., M. R. Hainey, I. N. Ross, et al. The ageing gut: a study of intestinal absorption in relation to nutrition in the elderly. Q. J. Med. 47: 197–211, 1978.
 306. Moog, R. The small intestine in old mice: growth, alkaline phosphatase and disaccharidase activities, and deposition of amyloid. Exp. Gerontol. 12: 223–234, 1977.
 307. Mooradian, A. D., and J. E. Morley. Micronutrient status in diabetes mellitus. Am. J. Clin. Nutr. 45: 877–895, 1987.
 308. Mooradian, A. D., and M. K. Song. The intestinal zinc transport in aged rats. Mech. Ageing Dev. 41: 189–197, 1987.
 309. Moore, J. G., D. J. Bjorkman, M. D. Mitchell, and A. Avots‐Avotins. Age does not influence acute aspirin induced gastric mucosal damage. Gastroenterology 100: 1626–1629, 1991.
 310. Moore, J. G., C. Tweedy, P. E. Christian, and F. I. Datz. Effect of age on gastric emptying of liquid‐solid meals in man. Dig. Dis. Sci. 14: 340–344, 1983.
 311. Morgan, Z., and M. Feldman. The liver, biliary tract and pancreas in the aged: an anatomic and laboratory evaluation. J. Am. Geriatr. Soc. 5: 59–65, 1957.
 312. Morris, H. A., B. E. C. Nordin, V. Fraser, T. F. Hartley, A. G. Need, and M. Horowitz. Calcium absorption and serum 1,25 dihydroxyvitamin D levels in normal and osteoporotic women. Gastroenterology 88: A1508, 1985.
 313. Mozcik, G. Y., E. Vetnter, M. Schmelczer, J. Kutas, L. Nagy, and F. Tarnok. A critical analysis of the gastric secretory response of patients with duodenal ulcer in dependence of their age and duration of symptoms. Acta Med. Hung. 38: 117–128, 1981.
 314. Multigner, L., H. Sarlex, D. Lombardo, and A. de Carlo. Pancreatic stone protein II. Implication in stone formation during the course of chronic calcifying pancreatitis. Gastroenterology 89: 387–391, 1985.
 315. Munroe, H. N., and V. R. Young. Protein metabolism in the elderly. Postgrad. Med. 63: 143–148, 1978.
 316. Murakami, M., J. Ishizuka, K. Yoshinaga, S. Sumi, G. A. Nichols, C. W. Cooper, G. H. Greeley, and J. C. Thompson. Age‐related changes in gallbladder contractility and cytoplasmic Ca++ concentration in the guinea pig. Gastroenterology 100: A539, 1991.
 317. Mylvaganam, K., P. R. Hudson, A. Herring, and C. P. Williams. 14C‐triolein breath test: an assessment in the elderly. Gut 30: 1082–1086, 1989.
 318. Nagai, H., and K. Ohtsubo. Pancreatic lithiasis in the aged—its clinicipathology and pathogenesis. Gastroenterology 86: 331–338, 1983.
 319. Nagengast, F. M., M. Hectors, S. D. J. van der Werf, and J. H. M. van Tongeren. Age dependent differences in secondary bile acid concentration in human feces. Gastroenterology 88: A1514, 1985.
 320. Nagy, Zs. The role of membrane structure and function in cellular aging: a review. Mech. Ageing Dev. 9: 237–246, 1979.
 321. Navah, F., and C. G. Winter. Effect of aging on intestinal absorption of aromatic amino acids in vitro in the rat. Am. J. Physiol. 254 (Gastrointest. Liver Physiol. 17): G630–G636, 1988.
 322. Necheles, H., F. Plotke, and J. Meyer. Studies on old age. V. Active pancreatic secretion in the aged. Am. J. Dig. Dis. 9: 157–159, 1942.
 323. Newton, R. B., J. L. Sullivan, and A. G. Debusk. Neutral amino acid transport and in vitro aging. Mech. Ageing Dev. 27: 63–72, 1984.
 324. Nokubo, M. Physical‐chemical and biochemical differences in liver plasma membranes in aging F‐344 rats. J. Gerontol. 40: 409–414, 1985.
 325. Nordin, C., V. Fraser, T. F. Hartley, A. G. Need, and M. Horowitz. Calcium absorption and serum 1,25 dihydroxy‐vitamin D levels in normal and osteoporotic women. Gastroenterology 88: A1508, 1985.
 326. Nordin, B. E. C., R. Wilkinson, D. H. Marshall, J. C. Gallagher, A. Williams, and M. Peacock. Calcium absorption in the elderly. Calc. Tissue Res. 21: 442–451, 1976.
 327. O'Connor, M. K., D. H. Kim, J. C. Y. Hung, and M. L. Brown. The effects of age, sex and bolus composition on esophageal transit. Gastroenterology 96: A371, 1989.
 328. Ogawa, K., H. Mukai, and M. Mori. Effect of ageing on proliferative activity of normal and carcinogen‐altered hepatocytes in rat liver after a two‐thirds partial hepatectomy. Jpn. J. Cancer Res. 76: 779–784, 1985.
 329. Ohta, M., and K. Kitani. Age‐dependent decrease in the hepatic uptake of taurocholic acid resembles that for ouabain. Biochem. Pharmocol. 39: 1223–1228, 1990.
 330. Ohtsubo, K., and T. A. Nomaguchi. A flow cytofluorometric study on age‐dependent ploidy class changes in mouse hepatocyte nuclei. Mech. Ageing Dev. 36: 125–131, 1986.
 331. Paganelli, G. M., R. Santucci, G. Biasco, M. Miglioli, and L. Barbara. Effect of sex and age on rectal cell renewal in humans. Cancer Lett. 53: 117–121, 1980.
 332. Parekh, D., K. Y. Yoshinaga, J. Ishizuka, C. M. Townsend, Jr., and J. C. Thompson. Age‐related increase in the severity and outcome of experimental peptic ulceration. Gastroenterology 100: A541, 1991.
 333. Pelot, D., J. V. Lorusso, and D. Hollander. The influence of aging on basal and secretin stimulated pancreatic exocrine secretion in the unanesthetized rat. Age 10: 1–4, 1987.
 334. Pénzes, L., G. Simon, and M. Winter. Intestinal absorption and utilization of radiomethionine in old age. Exp. Gerontol. 3: 257–263, 1968.
 335. Pénzes, L. Effect of concentration on the intestinal absorption of 1‐lysine in ageing rats. Exp. Gerontol. 4: 223–230, 1969.
 336. Pénzes, L. Intestinal transfer of 1–Arg in relation to age. Exp. Gerontol. 5: 193–201, 1970.
 337. Pénzes, L. Intestinal absorption of glycine, L‐alanine and L‐leucine in the old rat. Exp. Gerontol. 9: 245–252, 1974.
 338. Pénzes, L., and M. Boross. Intestinal absorption of some heterocyclic and aromatic amino acids from the ageing gut. Exp. Gerontol. 9: 253–258, 1974.
 339. Pénzes, L. Further data on the age‐dependent intestinal absorption of dibasic amino acids. Exp. Gerontol. 9: 259–262, 1974.
 340. Pénzes, L., D. Kranz, K. Kretschmar, V. Rosenthal, D. Januschkewitz, M. Kramer, and O. Regius. Alterations in the intestinal microvillous surface area during the whole life span of the female rat. Ileum. Z. Alternsforsch. 43: 251–258, 1988.
 341. Pesti, L., and J. A. Gordon. Effects of age and isolation on the intestinal flora of mice. Gerontologia 19: 153–161, 1973.
 342. Phillips, R. A., and H. Gilder. Metabolism studies in the albino rat. Endocrinology 27: 601–604, 1940.
 343. Piccione, P. R., P. R. Holt, J. A. Culpepper‐Morgan, et al. Intestinal dysmotility syndromes in the elderly: measurements of orocecal transit time. Am. J. Gastroenterol. 82: 161–164, 1990.
 344. Poston, G. J., E. J. Draviam, C. Z. Yao, C. M. Townsend, Jr., and J. C. Thompson. Effect of age and sensitivity to cholecystokinin on gallstone formation in the guinea pig. Gastroenterology 98: 993–999, 1990.
 345. Poston, G. J., R. Saydjari, J. Lawrence, R. W. Alexander, C. M. Townsend, Jr., and J. C. Thompson. The effect of age on small bowel adaptation and growth after proximal enterectomy. J. Gerontol. 45: B220–B225, 1990.
 346. Poston, G. J., R. Saydjari, J. P. Lawrence, C. M. Townsend Jr., and J. C. Thompson. Trophic effect of CCK, bombesin and pentagastarin on the aged rat pancreas. Pancreas 4: A637, 1989.
 347. Poston, G. J., P. Singh, E. J. Draviam, J. R. Upp, and J. C. Thompson. Development and age‐related changes in pancreatic cholecystokinin receptors and duodenal cholecystokinin in guinea pigs. Mech. Ageing Dev. 46: 59–66, 1988.
 348. Poston, G. J., P. Singh, and D. G. Maclellan, et al. Age‐related changes in gallbladder contractibility and gallbladder cholecystokinin receptor population in the guinea pig. Mech. Ageing Dev. 46: 225–236, 1988.
 349. Quastler, H., and F. G. Sherman. Cell population kinetics in intestinal epithelium in the mouse. Exp. Cell Res. 17: 420–438, 1959.
 350. Rabes, H. M., Liver cell turnover in man and animals during aging. In: Aging in Liver and Gastrointestinal Tract, edited by L. Bicuchi, P. R. Holt, O. F. W. James and R. N. Butler. Lancaster, UK: MTP Press, 1988, Falk Symposium 47, Titisee, 1987, p. 225–238.
 351. Rafsky, H. A., and B. Newman. Vitamin B1 excretion in the aged. Gastroenterology 1: 737–742, 1943.
 352. Rajakumar, G., M. K. Markus, and P.J. Scarpace. β‐Adren‐ergic receptors and salivary gland secretion during aging. Growth, Dev. Aging 56: 215–223, 1992.
 353. Rasmussen, S. N. Liver volume determination by ultrasonic scanning. Dan. Med. Bull. 25: 1–45, 1978.
 354. Read, N. W., W. V. Harford, A. C. Schmulen, M. G. Read, C. Santa Ana, and J. S. Fordtran. A clinical study of patients with fecal incontinence and diarrhoea. Gastroenterology 76: 747–756, 1979.
 355. Recker, R. R. Calcium absorption and achlorhydria. N. Engl. J. Med. 313: 70–73, 1985.
 356. Reville, M. F., F. Goose, J. Kachelhoffer, M. Doffoel, and F. Raul. Ileal compensation for age‐dependent loss of jejunal function in rats. J. Nutr. 121: 498–503, 1991.
 357. Richter, J. E., W. C. Wu, D. N. Johns, J. N. Blackwell, J. L. Nelson, J. A. Castell, and D. O. Castell. Esophageal manometry in 95 healthy adult volunteers. Variability of pressures with age and frequency of “abnormal” contractions. Dig. Dis. Sci. 32: 583–592, 1987.
 358. Rolandi, E., R. Franceschini, V. Messina, et a, Somatostatin in the elderly: diurnal plasma profile and secretory response to meal stimulation. J. Gerontol. 33: 296–301, 1987.
 359. Roncucci, L., M. Ponz de Leon, A. Scalmati, G. Malagoli, S. Pratissoli, M. Perine, and N. J. Chahin. The influence of age on colonic epithelial cell proliferation. Cancer 62: 2373–2377, 1988.
 360. Rosenberg, T. I., N. Friedland, H. D. Janowitz, and D. A. Dreiling. The effect of age and sex upon human pancreatic secretion of fluid and bicarbonate. Gastroenterology 50: 191–194, 1966.
 361. Rowlatt, C., Cell aging in the intestinal tract. In: Advances in Experimental Medicine and Biology. Vol. S3. Cell Impairment in Aging Development, edited by V. Cristofalo and E. Holeckova. New York: Plenum Press, 1975, p. 215–217.
 362. Ruggeri, B., The effects of caloric restriction on neoplasia and age‐related degenerative processes. In: Cancer and Nutrition, edited by R. B. Alfin‐States and D. Kritchevsky. New York: Plenum Press, 1991, p. 197–210.
 363. Russell, R. M., S. D. Krasinski, I. M. Samloff, et al. Folic acid malabsorption in atrophic gastritis. Gastroenterology 91: 1476–1482, 1986.
 364. Said, H. M., D. Horne, and D. Mock. Influence of aging on intestinal biotin transport in the rat. Gastroenterology 96: A435, 1989.
 365. Sanstead, H. H., L. K. Henriksen, J. L. Greger, et al. Zinc nutriture in the elderly in relation to taste acuity, immune response and wound healing. Am. J. Clin. Nutr. 36: 1046–1059, 1982.
 366. Santer, R. M., and D. M. Baker. Enteric neuron numbers and sized in Auerbach's plexus in the small and large intestine of young adult and aged rats. J. Auton. Nerv. Syst. 25: 59–67, 1988.
 367. Sato, T., and H. Tauchi. The formation of enlarged and giant mitochondria in the aging process of human hepatic cells. Acta Pathol. Jap. 25: 403–412, 1975.
 368. Saweirs, W. M., D. J. Andrews, and T. S. Low‐Beer. The double sugar test of intestinal permeability in the elderly. Age Ageing 14: 312–315, 1985.
 369. Sayeed, M. Age‐related changes in intestinal phosphomonoesterases. Fed. Proc. 26: 259, 1967.
 370. Schaedler, R. W., R. Duros, and R. Costello. The development of the bacterial flora in the gastrointestinal tract of mice. J. Exp. Med. 122: 59–66, 1965.
 371. Schmitz‐Moorman, P., G. W. Himmelmann, J. W. Brondes, et al. Comparative radiological and morphological study of human pancreas: pancreatitis‐like changes in post‐mortem ductograms and their morphological pattern. Gut 26: 406–414, 1985.
 372. Schmucker, D. L., and R. K. Wang. Age‐dependent alterations in rat liver microsomal NADPH‐cytochrome c (P‐450) reductase: a qualitative and quantitative analysis. Mech. Ageing Dev. 21: 137–156, 1983.
 373. Schmucker, D., and R. Wang. Effects of aging on the properties of rhesus monkey liver microsomal NADPH cytochrome c (P‐450) reductase. Drug Metab. Disp. 15: 225–232, 1987.
 374. Schnegg, M., and B. H. Lauterburg. Quantitative liver function in the elderly assessed by galactose elimination capacity, aminopyrine demethylation and caffeine clearance. J. Hepatol. 3: 164–171, 1986.
 375. Schmucker, D. L., R. Gilbert, A. L. Jones, G. T. Hradek, and H. Bazin. Effect of aging on the hepatobiliary transport of dimeric immunoglobulin A in the male Fisher rat. Gastroenterology 88: 436–443, 1985.
 376. Schuette, S. A., N. J. Yasillo, and C. M. Thompson. The effect of carbohydrates in milk on the absorption of calcium by postmenopausal women. J. Am. Coll. Nutr. 10: 132–139, 1991.
 377. Shaker, R., Q. Li, J. Ren, W. F. Townsend, W. J. Dodds, B. J. Martin, M. K. Kern, and A. Rynders. Coordination of deglutition and phases of respiration: effect of aging tachypnea, bolus volume, and chronic obstructive pulmonary disease. Am. J. Physiol. 263 (Gastrointest. Liver Physiol. 26): G750–755, 1992.
 378. Shankle, W. R., B. H. Landing, S. M. A. H. Chui, G. Villarreal‐Engelhardt, and C. Zarow. Studies of the enteric nervous system in Alzheimer disease and other dementias of the elderly: enteric neurons in Alzheimer disease. Mod. Pathol. 6: 10–14, 1993.
 379. Sheikh, M. S., A. Ramirez, M. Emmett, C. Santa Ana, L. R. Schiller, and J. S. Fordtran. Role of vitamin D‐dependent and vitamin D‐independent mechanisms in absorption of food calcium. J. Clin. Invest. 81: 126–132, 1988.
 380. Ship, J. A., C. Decarli, R. P. Friedlnand, and B. J. Baum. Diminished submandibular salivary flow in dementia of the Alzheimer type. J. Gerontol. 45: M61–M66, 1990.
 381. Shub, M. D., K. Y. Pang, D. A. Swann, and W. A. Walker. Age‐related changes in chemical composition and physical properties of mucus glycoproteins from rat small intestine. Biochem. J. 215: 405–411, 1983.
 382. slmanowski, U. A., P. Suter, F. Stickel, H. Maier, R. Waldherr, R. M. Russell, and H. K. Seitz. Esophageal epithelial hyperregeneration following chronic ethanol consumption: effect of age and saliva. Gastroenterology 102: A398, 1992.
 383. Simko, V., and S. Michael. Absorptive capacity for dietary fat in elderly patients with debilitating disorders. Arch. Intern. Med. 149: 557–560, 1989.
 384. Singh, P., B. Rae‐Venter, C. M. Townsend, Jr., T. Khalil, and J. C. Thompson. Gastrin receptors in normal and malignant gastrointestinal mucosa: age‐associated changes. Am. J. Physiol. 249 (Gastrointest. Liver Physiol. 12): G761–G769, 1985.
 385. Siurala, M., M. Isokoski, K. Varis, and M. Kekki. Prevalence of gastritis in a rural population. Scand. J. Gastroenterol. 3: 211–223, 1968.
 386. Snook, J. T. Effect of age and long‐term diet on exocrine pancreas of the rat. Am. J. Physiol. 228: 262–268, 1975.
 387. Soergel, K. H., F. F. Zboralske, and J. R. Amberg. Presbyesophagus: esophagus motility in nonagenarians. J. Clin. Invest. 48: 1472–1478, 1964.
 388. Southgate, D. A. T., and J. V. G. A. Durnin. An experimental reassessment of the factors used in the calculation of the energy value of human diets. Br. J. Nutr. 24: 517–535, 1970.
 389. Spence, R. A. J., B. J. Collins, T. G. Parks, and A. H. G. Love. Does age influence normal gastro‐oesophageal reflux? Gut 26: 799–801, 1985.
 390. Stanbridge, E. S. Human tumor suppressor genes. Annu. Rev. Genet. 24: 615–657, 1990.
 391. Starzl, T. E., R. Gordon, A. Tzakis, W. Marsh, and D. Van Thiel. Liver transplantation in older patients. N. Engl. J. Med. 316: 484–485, 1987.
 392. Steinbach, G., S. P. Kumar, B. S. Reddy, M. Lipkin, and P. R. Holt. Divergent effects of dietary calories and fat on rat colonic cell proliferation. Cancer Res. 33: 2745–2749, 1993.
 393. Sun, J., and H. W. Strobel. Aging affects the drug metabolism systems of rat liver, kidney, colon and lung in a differential fashion. Exp. Gerontol. 21: 523–534, 1986.
 394. Sun, W. M., T. C. Donnelly, and N. W. Read. Utility of a combined test of anorectal manometry, electromyography, and sensation in determining the mechanism of “idiopathic” faecal incontinence. Gut 33: 807–813, 1992.
 395. Suntzeff, V., and P. Angeletti. Histological and histochemical changes in intestines of mice with aging. J. Gerontol. 16: 225–229, 1951.
 396. Suter, P. M., B. B. Golner, B. R. Goldin, F. D. Morrow, and R. M. Russell. Reversal of protein‐bound vitamin B12 malabsorption with antibiotics in atrophic gastritis. Gastroenterology 101: 1039–1045, 1991.
 397. Szewczuk, J. R., and R. J. Campbell. Differential effect of aging on the heterogeneity of the immune response to a T‐dependent antigen in systemic and mucosal‐associated lymphoid tissues. J. Immunol. 126: 472–477, 1981.
 398. Szewczuk, M. R., R. J. Campbell, and L. K. Jung. Lack of age‐associated immune dysfunction in mucosal‐associated lymph nodes. J. Immunol. 128: 2200–2204, 1981.
 399. Szurszewski, J. H., P. R. Holt, and M. Schuster, Proceedings of a workshop entitled “Neuromuscular function and dysfunction of the gastrointestinal tract in aging.” Dig. Dis. Sci. 34: 1135–1146, 1989.
 400. Taillefer, R., M. Jadiawalla, E. Pellerin, E. Lafontaine, and A. Duranceau. Radionuclide esophageal transit study in detection of esophageal motor dysfunction: comparison with motility studies (manometry). J. Nucl. Med. 31: 1921–1926, 1990.
 401. Takamoto, S., Y. Seino, B. Sackor, and C. T. Liang. Effect of age on duodenal 1,25‐dihydroxyvitamin D‐3 receptors in Wistar rats. Biochim. Biophys. Acta 1034: 22–28, 1990.
 402. Taylor, L. D., C. K. Daniels, and D. L. Schmucker. Does aging impair gastrointestinal mucosal immunity. Aging 2: 205–209, 1990.
 403. Taylor, L., E. Schneider, J. Smith, and P. Polgar. Prostaglandin production and cellular aging. Mech. Ageing Dev. 16: 311–317, 1981.
 404. Texter, E. C., and H. J. Jordan. The effect of vascular factors on nutrient absorption. In: Handbook of Nutrition and Food, edited by M. Rechcigl. Boca Raton, FL: CRC Press, 13–20, 1983.
 405. Thompson, E. N., and R. Williams. Effect of age on liver function with particular reference to bromsulphalein excretion. Gut 6: 266–269, 1965.
 406. Thompson, J. S., D. A. Crouse, S. I. Mann, S. K. Saxena, and J. G. Sharp. Intestinal glucose uptake is increased in aged mice. Mech. Ageing Dev. 46: 135–143, 1988.
 407. Thomson, A. B. R. Unstirred water layer and age dependent changes in rabbit jejunal D glucose transport. Am. J. Physiol. 236 (Endocrinol. Metab. Gastrointest. Physiol. 5): E685–691, 1979.
 408. Thomson, A. B. R. Effect of age on uptake of homologous series of saturated fatty acids into rabbit jejunum. Am. J. Physiol. 239 (Gastrointest. Liver Physiol. 2): G363–371, 1980.
 409. Thomson, A. B. R. Aging and cholesterol uptake in the rabbit jejunum. Role of the bile salt micelle and the unstirred water layer. Dig. Dis. Sci. 26: 890–896, 1981.
 410. Thomson, A. D. Thiamine absorption in old age. Gerontol. Clin. 8: 354–361, 1966.
 411. Thrasher, J. D. Age and the cell cycle of the mouse esophageal epithelium. Exp. Gerontol. 6: 19–24, 1971.
 412. Thrasher, J. D., and R. C. Greulich. The duodenal progenitor population. I. Age related increase in the duration of the cryptal progenitor cycle. J. Exp. Zool. 159: 39–46, 1965.
 413. Tiscornia, O., M. A. Cresta, E. S. de Lehmann, D. Celener, and D. A. Dreiling. Effects of sex and age on pancreatic secretion. Int. J. Pancreatol. 1: 95–118, 1986.
 414. Tomotari, M. Intestinal flora and aging. Nutr. Rev. 50: 438–446, 1992.
 415. Tracy, J. F., J. A. Logemann, P. J. Kahrilas, P. Jacob, M. Kobara, and C. Krugler. Preliminary observations on the effects of age on oropharyngeal deglutition. Dysphagia 4: 90–94, 1989.
 416. Trudeau, W. L., and J. E. McGuigan. Serum gastrin levels in patients with peptic ulcer disease. Scand. J. Gastroenterol. 6: 9–46, 1970.
 417. Tuchweber, B., A. Perea, G. Ferland, and I. M. Yousef. Dietary restriction influences bile formation in aging rats. Life Sci. 41: 2091–2099, 1987.
 418. Turead, J., and A. P. N. Majumdar. Phorbol ester induced changes in colonic mucosal tyrosine kinase and epidermal growth factor receptor during aging. Gastroenterology 98: A434, 1990.
 419. Turnland, J. R., N. Durkin, F. Costa, and S. Margen. Stable isotope studies of zinc absorption and retention in young and elderly men. J. Nutr. 116: 1239–1247, 1986.
 420. Turnlund, J. R., M. C. Michel, W. R. Keyes, Y. Schutz, and S. Margen. Copper absorption in elderly men determined by using 65Cu. Am. J. Clin. Nutr. 36: 587–591, 1982.
 421. Turnlund, J. R., D. Reager, B. S. Reager, and F. Costa. Iron and copper absorption in young and elderly men. Nutr. Res. 8: 333–343, 1988.
 422. Turusov, V. S., N. S. Lanko, and Y. D. Parfenov. Effect of age on induction of intestinal tumors in mice by 1,2‐dimethyl‐hydrazine. Oncology 1681–1683, 1982.
 423. Uchida, K., Y. Nomura, M. Kadowaki, H. Takase, K. Takano, and N. Takeuchi. Age‐related changes in cholesterol and bile acid metabolism in rats. J. Lipid Res. 19: 544–552, 1978.
 424. Valdivieso, V., R. Palma, R. Wunkhaus, C. Antezana, C. Severin, and A. Contreras. Effect of aging on biliary lipid composition and bile acid metabolism in normal Chilean women. Gastroenterology 74: 871–874, 1978.
 425. van der Werf, S. D. J., A. W. M. Huijbregts, H. L. M. Lamers, G. P. van Berge Henegouwen, and J. H. M. van Tongeren. Age dependent differences in human bile acid metabolism and 7‐alpha‐dehydroxylation. Eur. J. Clin. Invest. 11: 425–431, 1981.
 426. Van Lennep, E. W. The histology of the mucosa of the small intestine of the long‐nosed bandicoot with special reference to the intestinal secretion. Acta Anat. 50: 73–89, 1962.
 427. Van Liere, E. J., and D. W. Northup. The emptying time of the stomach of old people. Am. J. Physiol. 134: 719–722, 1941.
 428. Vantrappen, G., J. Janssens, J. Hellemans, and Y. Ghoos. The interdigestive motor complex of normal subjects and patients with bacterial overgrowth of the small intestine. J. Clin. Invest. 59: 1158–1166, 1977.
 429. Vanzant, F. R., W. C. Alverez, G. B. Essterman, H. L. Dunn, and J. Berkson. The normal range of gastric acidity from youth to old age. Arch. Intern. Med. 49: 345–359, 1932.
 430. Varga, F. Transit time changes with age in the gastrointestinal tract of the rat. Digestion 14: 319–324, 1976.
 431. Varga, F., and T. Z. Csaky. Changes in the blood supply of the gastrointestinal tract in rats with age. Pflugers Arch. 364: 129–133, 1976.
 432. Vellas, B., D. Balas, J. Moreau, M. Bouisson, F. Senegas‐Balas, M. Guidet, and A. Ribet. Exocrine pancreatic secretion in the elderly. Int. J. Pancreatol. 3: 497–502, 1988.
 433. Vestal, R. E., A. J. J. Wood, R. J. Branch, et al. Studies of drug disposition in the elderly using model compounds. In: Liver and Aging, edited by K. Kitani. Amsterdam: Elsevier, 1978, p. 343–355.
 434. Vinardell, M. P., and J. Bolufer. Age dependent changes in jejunal sugar absorption by rat in vivo. Exp. Gerontol. 19: 73–78, 1984.
 435. Vinardell, M. P., and J. Bolufer. Active/diffusion ratio of sugars intestinal absorption at different ages in rats. Nutr. Rep. Int. 33: 199–209, 1986.
 436. Vincenzini, M. T., T. Iantomasi, M. Stio, F. Favilli, P. Vanni, F. Tonelli, and C. Treves. Glucose transport during ageing by human intestinal brush‐border membrane vesicles. Mech. Ageing Dev. 48: 33–41, 1989.
 437. Wahby, M. A., and P. N. Majumdar. Diminished activation of tyrosine kinases by gastrin in isolated gastric mucosal cells from aged rats. Proc. Soc. Exp. Biol. Med. 202: 365–370, 1993.
 438. Wahnon, R., S. Makady, and U. Cogan. Age and membrane fluidity. Mech. Ageing Dev. 50: 249–255, 1989.
 439. Wall, W. J., R. Mimeault, D. R. Grant, and M. Block. The use of older donor livers for hepatic transplantation. Transplantation 49: 377–381, 1990.
 440. Wallace, S., and C. Ashworth. Early degenerative lesions of the pancreas. Tex. State J. Med. 37: 584–587, 1942.
 441. Walling, M. W., and S. S. Rothman. Apparent increase in carrier affinity for intestinal calcium transport following dietary calcium restriction. J. Biol. Chem. 245: 5007–5011, 1970.
 442. Wallis, J. L., and B. H. Hirst. Glucose uptake by aged mouse jejunal brushborder membrane vesicles. Proc. Int. Union Physiol. Sci. XCII: 52, 1989.
 443. Wallis, J. L., P. S. Lipski, J. C. Mathers, O. F. W. James, and B. H. Hirst. Duodenal brush‐border mucosal glucose transport and enzyme activities in ageing man and the effect of bacterial contamination of the small intestine. Dig. Dis. Sci. 38: 403–409, 1993.
 444. Walsh, J., C. Richardson, and J. Fortran. pH dependence of acid secretion and gastrin release in normal and ulcer patients. J. Clin. Invest. 55: 462–469, 1972.
 445. Wanstall, J. C., and S. R. O'Donnell. Vasodilator responses to dopamine in rat perfused mesentery are age‐dependent. Br. J. Pharmacol. 98: 302–308, 1989.
 446. Warren, P. M., M. A. Pepperman, and R. D. Montgomery. Age changes in small intestinal mucosa. Lancet ii: 849, 1978.
 447. Watanabe, T., and Y. Tanaka. Age‐related alternations in the size of human hepatocytes. A study of mononuclear and binucleate cells. Virchows Arch. (B) Cell Pathol. Incl. Mol. Pathol. 39: 9–20, 1982.
 448. Webster, S. G. P., and J. T. Leeming. The appearance of the small bowel mucosa in old age. Age Ageing 4: 168–174, 1975.
 449. Webster, S. G. P., and J. T. Leeming. Assessment of small bowel function in the elderly using s modified xylose tolerance test. Gut 16: 109–113, 1975.
 450. Webster, S. G. P., E. M. Wilkinson, and E. Gowland. A comparison of fat absorption in young and old subjects. Age Ageing 6: 113–117, 1977.
 451. Wegener, M. G., J. Scharffstein, J. Luth, R. Rickels, and D. Ricken. Effect of ageing on the gastro‐intestinal transit of a lactulose supplemental solid‐liquid meal in humans. Digestion 39: 40–46, 1988.
 452. Weiner, P. G., F. Dietze, and R. Laue. Age‐dependent alterations of intestinal absorption. II. A clinical study using a modified D‐xylose absorption test. Arch. Gerontol. Geriatr. 3: 97–108, 1984.
 453. Welsh, J. D., J. R. Poley, M. Bhatia, and D. E. Stevenson. Intestinal disaccharidase activities in relation to age, race and mucosal damage. Gastroenterology 75: 847–855, 1978.
 454. Wermer, I., and L. Hambraeus. The digestive capacity of elderly people. In: Nutrition in Old Age, edited by L. A. Carlson. Uppsala, Sweden: Almquist and Wicksell, 1972, p. 55–60.
 455. Williamson, R. C. N. Intestinal adaptation: structural, functional, and cytokinetic changes. N. Engl. J. Med. 298: 1393–1401, 1978.
 456. Wolff, A., P. C. Fox, J. A. Ship, J. C. Atkinson, A. A. Macynski, and B. J. Baum. Oral mucosal status and major salivary gland function. Oral Surg. Oral Med. Oral Pathol. 70: 49–54, 1990.
 457. Woodhouse, K. W., F. Williams, E. Mutch, H. Wynne, M. Rawlins, and O. F. W. James. Phase 1 drug metabolism in aging. In: Aging in Liver and Gastrointestinal Tract, edited by L. Bianchi, P. R. Holt, O. F. W. James, and R. N. Butler. Lancaster, UK: MTP Press, 1988, Falk Symposium 47, Titisee, 1987, p. 255–265.
 458. Wormsley, K. G., and M. I. Grossman. Maximal histalog test in control subjects and patients with peptic ulcer. Gut 6: 427–435, 1965.
 459. Wright, R. A., S. Krinsky, L. Fleeman, J. Trujillo, and E. Teague. Gastric emptying and obesity. Gastroenterology 84: 747–751, 1983.
 460. Wynne, H. A., L. H. Cope, E. Mutch, M. D. Rawlins, K. W. Woodhouse, and O. F. W. James. The effect of age upon liver volume and apparent liver blood flow in healthy men. Hepatology 9: 297–301, 1989.
 461. Yoshinaga, K., J. Ishizuka, R. Saydjari, C. M. Townsend, Jr., and J. C. Thompson. Effect of aging on polyamine pathway of small intestine in the rat. Dig. Dis. Sci. 38: 410–416, 1993.
 462. Yu, B. P., E. A. Suescun, and S. Y. Yang. Effect of age‐related lipid peroxidation on membrane fluidity and phospholipase A2 modulation by dietary restriction. Mech. Ageing Dev. 65: 17–33, 1992.
 463. Yu, B. P., E. A. Suescun, and S. Y. Yang. Effect of age‐related lipid peroxidation on membrane fluidity and phospholipase A2: modulation by dietary restriction. Mech. Ageing Dev. 65: 17–33, 1992.
 464. Zenker, F. A., and H. Von Ziemssen. Dilatations of the esophagus. In: Cyclopaedia of the Practice of Medicine. London: Low, Marston, Searle and Rivington, 1878, p. 46–68.
 465. Zhu, H., F. Pace, O. Sangaletti, and B. Porro. Features of symptomatic gastroesophageal reflux in elderly patients. Scand. J. Gastroenterol. 28: 235–238, 1993.
 466. Zimmerman, J. A., and T. H. Carter. Altered cellular responses to chemical carcinogens in aged animals. J. Gerontol. 44: B19–B24, 1989.
 467. Zimmerman, V. W., N. Frank, C. Weib‐Simon, et al. Das normals pankreas‐darstellung in sonogramm in abhangigkeit zum lebensalter. Fortschr. Med. 99: 1178–1182, 1981.
 468. Zoli, M., T. Iervese, S. Abbati, G. P. Bianchi, G. Marchesini, and E. Pisi. Portal blood velocity and flow in aging man. Gerontology 35: 61–65, 1989.

Contact Editor

Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite

Peter R. Holt. The Gastrointestinal Tract. Compr Physiol 2011, Supplement 28: Handbook of Physiology, Aging: 505-554. First published in print 1995. doi: 10.1002/cphy.cp110120