Composition of basal and stimulated hepatic bile in baboons, and the formation of cholesterol gallstones.

The baboon, Papio, has been found to be a model for the study of the pathogenesis of cholesterol cholelithiasis in man. Studies of the physiologic variations in hepatic bile composition indicate a cyclic pattern to the proportions of cholesterol, lecithin, and bile salt in hepatic bile. During reabsorption of the bile salt pool from the intestines (stimulated flow), hepatic bile is characteristically undersaturated with cholesterol. After reabsorption of the bile salt pool (basal flow), hepatic bile is characteristically supersaturated with cholesterol. This typical pattern of basal and stimulated hepatic bile occurs irrespective of the presence of cholesterol stones in the baboon. Recognition of these two types of hepatic bile and their interrelationship during admixture in the gallbladder provides new insight into the pathogenesis of gallstone formation.