Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 52, Issue 6 B300-B310, Copyright © 1997 by The Gerontological Society of America

JOURNAL ARTICLE

Effects of changes in calorie intake on intestinal nutrient uptake and transporter mRNA levels in aged mice

DM Casirola, Y Lan and RP Ferraris
Department of Pharmacology and Physiology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, USA.

In aged, chronically calorie-restricted (CR) mice, intestinal nutrient uptake is significantly higher than in same-age ad libitum controls. Can this chronic restriction-induced enhancement of uptake be reversed by ad libitum feeding? We addressed this question by switching 32-mo- old chronically CR mice to ad libitum feeding for 4 wk (CRAL). Intestinal transport rate and total intestinal absorptive capacity for D-sugars and several nonessential L-amino acids decreased significantly in CRAL mice. In contrast, switching CR mice to an ad libitum regimen for only 3 d had no effect on intestinal nutrient transport, indicating that the negative effects of ad libitum feeding require a duration longer than the 3-d lifetime of most enterocytes. Permeability of the intestinal mucosa to L-glucose was independent of the switches in diet. Levels of the brushborder glucose transporter SGLT1, brushborder fructose transporter GLUT5, and basolateral sugar transporter GLUT2 mRNA as determined by reverse transcriptase-polymerase chain reaction in 6-, 24-, and 32-mo-old mice were each apparently independent of caloric restriction and age. We conclude that the high rates of intestinal nutrient uptake exhibited by chronically CR mice can be reversed by ad libitum feeding of only 1 mo duration. These decreases in uptake were due mainly to specific decreases in transport per unit weight of intestine and not to nonspecific decreases in intestinal mass. Changes in rates of sugar uptake induced by chronic CR and age are apparently not accompanied by changes in steady-state levels of mRNA coding for those transporters.

This article has been cited by other articles: (Search Google Scholar for Other Citing Articles)

				L. Jiang, E. S. David, N. Espina, and R. P. Ferraris GLUT-5 expression in neonatal rats: crypt-villus location and age-dependent regulation Am J Physiol Gastrointest Liver Physiol, September 1, 2001; 281(3): G666 - 674. [Abstract] [Full Text] [PDF]

				R. P. Ferraris, Q.-X. Cao, and S. Prabhakaram Chronic but Not Acute Energy Restriction Increases Intestinal Nutrient Transport in Mice J. Nutr., March 1, 2001; 131(3): 779 - 786. [Abstract] [Full Text]

				L. Jiang and R. P. Ferraris Developmental reprogramming of rat GLUT-5 requires de novo mRNA and protein synthesis Am J Physiol Gastrointest Liver Physiol, January 1, 2001; 280(1): G113 - 120. [Abstract] [Full Text]