Human colonic adenylate cyclase: effects of bile acids

Abstract

Three different bile acids, deoxycholic acid, chenodeoxycholic acid and ursodeoxycholic acid, were tested for their capacity to stimulate the adenylate cyclase in human colonic mucosa. This enzyme system was sensitive towards vasoactive intestinal polypeptide and prostaglandin E2. These 3 bile acids were ineffective in activating the human cyclase system over a wide concentration range tested. Concentrations above 1 .times. 10-5 mmol/l induced a dose-dependent inhibition of basal enzyme activity. Bile-acid induced diarrhea may not be associated with activation of the membrane-bound adenylate cyclase system in man.