Effect of 1,25-dihydroxycholecalciferol on ethanol mediated suppression of calcium absorption.

Rats raised on laboratory diet and given 20% ethanol in water as a sole source of fluid for 12 days were given 0.2 mug of 1,25-dihydroxycholecalciferol 24 h before measuring duodenal calcium transport by an in vitro everted gut sac technique. This vitamin D metabolite did not reverse the ethanol-induced inhibitiom of transport capacity. Ultrastructural studies of intestinal epithelial cells from animals ingesting ethanol demonstrated changes in mitochondria and other subcellular organelles as well as accumulation of electron-dense, calcium-containing granules in microvilli and a paucity of granules in mitochondria. The results suggest that the inhibition is mediated at the intestinal level, affecting mechanisms which are probably independent of Vitamin D, and in part by an interference in transport of calcium from microvilli to other intracellular sites.