Biliary Lipid Secretion Rates Research Articles

Effects of Low Dose Chenodeoxycholic Acid Feeding on Biliary Lipid Metabolism

To better define the mechanisms by which chenodeoxycholic acid (CDCA) alters the lipid composition of bile and promotes dissolution of cholesterol gallstones, we have studied the effects of relatively low doses of CDCA on the metabolism of biliary lipids in 10 subjects without gallstones. In 5 subjects, the effects of CDCA feeding were compared to those of cholic acid, a bile acid that apparently does not dissolve cholesterol stones. The following measurements were carried out during control and treatment periods: (1) composition of biliary lipids, (2) hepatic secretion rates of biliary lipids, (3) pool sizes of bile acids, and (4) specific composition of bile acids. Low doses of CDCA consistently reduced the lithogenicity of gallbladder bile by decreasing the proportion of cholesterol relative to the solubilizing lipids--bile acids and lecithin. This decrease in lithogenicity was associated with a selective reduction in hepatic secretion rates of cholesterol. At the doses of CDCA given, secretion rates of bile acids and lecithin and pool sizes of bile acids were not significantly changed; also conversion of cholesterol into bile acids was not completely inhibited. Cholic acid feeding appeared to increase the total size of the bile acid pool, but it did not affect the lithogenicity of bile or secretion rates of cholesterol. The data show that at low doses CDCA lowers lithogenicity of bile by reducing hepatic secretion of cholesterol, while cholic acid does not have a similar effect.

Biliary Lipid Secretion Before and After Cholecystectomy in American Indians with Cholesterol Gallstones

The effects of cholecystectomy on the hepatic secretion rates of biliary lipids and the relative lipid composition of hepatic bile were examined in 8 American Indian patients with cholesterol gallstones. Using a marker dilution technique, the hepatic secretion rates of cholesterol, bile acids, and phospholipids were measured during continuous duodenal infusion of formula before and several months after cholecystectomy. Before surgery, the Indian patients with gallstones secreted hepatic bile that was more lithogenic than that in a group of white women without stones. When bile was sampled under identical conditions after cholecystectomy, there was no change in biliary lipid composition or in hepatic secretion rates. Thus, cholecystectomy apparently does not correct the defect leading to lithogenic bile in these patients.