Glucose transport during ageing by human intestinal brush-border membrane vesicles

Glucose absorption by the small intestine is a complex phenomenon, that can be successfully studied by means of isolated brush-border and basolateral membrane vesicles of the enterocytes. We have carried out transport experiments on isolated brush-border membrane vesicles from the human small intestine, taking into account the age of the subjects. Our studies demonstrated that Na+-glucose cotransporter activity decreased as age increased with the "overshoot" phenomenon disappearing altogether in the oldest subjects. This effect was compared to that observed in intestinal membrane vesicles of young patients suffering from Crohn's disease; in this case there was a marked decrease in the Na+-dependent D-glucose uptake, but the "overshoot", even though low, was present. K+-dependent D-glucose transport, diffusion of L-glucose and the levels of some enzyme markers for intestinal brush-border membranes were also studied.