Small intestinal permeability in animals and man

Abstract

The permeability of the human small intestine was studied by measuring the clearance from the plasma into the intestinal lumen of substances with molecular weights ranging from 60 to 80000. A direct relationship was demonstrated between intestinal loss and plasma concentration and an inverse one between clearance and molecular size. The permeability of the rabbit small intestine was studied at various levels by measuring the blood to lumen clearance of substances of different molecular size ranging from 60 to 40000. It was demonstrated that there is a progressive fall in permeability from the duodenum to the terminal ileum for all the substances studied.