Effect of ursodeoxycholic acid on biliary lipid coupling and on cholesterol absorption during fasting and eating in subjects with cholesterol gallstones.

The aim of this study was to determine the effect of chronic ursodeoxycholic acid administration on coupling of bile acids with cholesterol and phospholipid in hepatic bile, and on cholesterol absorption in the duodenum. A range of bile acid secretion rates was obtained during an evening meal and an overnight fast. Duodenal perfusion of polyethylene glycol as a nonabsorbable recovery marker and of [3H]cholesterol and [14C]lecithin as absorbable recovery markers was combined with continuous intravenous infusion of indocyanine green as a hepatic bile marker. Six subjects with gallstones were studied before and during chronic administration of ursodeoxycholic acid (675 mg/day). Duplicate pretreatment studies revealed good reproducibility for biliary lipid coupling and cholesterol absorption. During ursodeoxycholic acid administration there was a significant alteration not only in bile acid/cholesterol coupling (p less than 0.001), but also in bile acid/phospholipid coupling (p less than 0.001). Mean cholesterol absorption decreased from 25% to 15% (p less than 0.001) during ursodeoxycholic acid administration. These effects of chronic ursodeoxycholic acid administration on biliary lipid coupling are similar to those reported for acute administration, and are thus consistent with an effect caused by bile acid lipid-solubilizing capacity.