Vitamin D and permeability of intestinal mucosa to calcium

Abstract

The role of the permeability of intestinal mucosa to calcium was determined in rats by comparison of calcium transport in vitro across the wall of everted intestinal loops from which the mucosal epithelium was removed and of loops with intact epithelium. Energy-dependent transport systems were inhibited by incubation at 5 C or by addition of N-ethyl maleimide to the medium. The experiments were designed to measure calcium transport along a concentration gradient between mucosal and serosal surfaces at varying concentrations of calcium in the mucosal solution. The results indicate that the intact intestinal mucosa presents a diffusion barrier to calcium and that this diffusion barrier is lessened by vitamin D treatment of the animal from which the intestine is obtained.