Rat small intestine absorption and membrane digestion in the process of aging

Sergey T Metelsky

doi:10.4236/jbpc.2013.42009

Abstract

Recently, in our experiments, we used the short-circuit current technique to study the kinetic constants for nutrient transporters in rat gastric-intestinal tract and the thickness of the intestinal unstirred layer near the mucosa surface. It was shown that, during the process of aging, the number of nutrient monomer transporters in the small intestine increases twofold, whereas the affinity of transporters to the correspondent nutrients remains unchanged. The situation for peptides may be opposite. The layer thickness in the vicinity of the mucosa surface, measured through glucose, decreased during the process of aging. It was suggested that, in old rats, the role of the digestive volume is more important, which results in an increase of the number of nutrient monomer transporters.

Highlights

It has long been known that aging is accompanied by changes in the functions of the GI tract, in particular, absorption and membrane digestion [1,2,3]
Results [1] indicate, that age reduces in vitro intestinal glucose uptake in the rat, but age-associated decline in glucose uptake was not explained by alterations in SGLT1
Like in [22], these findings suggest that impaired carbohydrate absorption due to aging is related to factors other than diminished mucosal glucose uptake

Summary

Introduction

It has long been known that aging is accompanied by changes in the functions of the GI tract, in particular, absorption and membrane digestion [1,2,3]. Data on the influence of aging on the absorption of nutrients are contradictory [1,4,5,6,7,8,9,10] Between all these studies, there are more differences (research methods, objects of study, the age of the animals, the localization of resected intestine, etc.) than the similarities. There are more differences (research methods, objects of study, the age of the animals, the localization of resected intestine, etc.) than the similarities One reason for these contradictions may be the fact that absorption in the intestine may be performed in several ways and each mechanism of nutrients absorption may depend on the age differently. Results [1] indicate, that age reduces in vitro intestinal glucose uptake in the rat, but age-associated decline in glucose uptake was not explained by alterations in SGLT1

Results

Discussion

Conclusion