Age-related changes in jejunal glucose absorption in mice

Abstract

Jejunal glucose absorption was determined in male mice aged 1, 2, 6, 12, and 18 months of age. Active and passive glucose transport was measured in vitro by estimating the uptake of 3-0-methyl-D-glucose by 1 mm jejunal rings in the presence and absence of phlorizin over a 5 min period. Passive glucose transport was found to be constant with increasing age. Active transport peaked at 2 months of age and the steadily declined. The reduction in active glucose transport rate between 2 and 18 months of age was approximately 50%. No corresponding changes were noted for jejunal villus or crypt dimensions, thickness of the jejunal musculature, or mucosal water and protein content. The age-related decrease in absorption is initiated before attainment of mature body weight. These results demonstrate that age specifically modifies active transport function in mouse jejunal mucosa without concomitant alterations in the structure of the jejunal wall.