Effects of meals and interruption of enterohepatic circulation on flow, lipid composition, and cholesterol saturation of bile in man after cholecystectomy

In 4 patients studied after cholecystectomy and common-duct exploration for cholesterol gallstones, bile salt (BS) and phospholipid (PL) output and bile flow increased significantly in response to breakfast, but cholesterol (Ch) output was unaltered. Simultaneously, Ch concentration decreased while PL and BS concentrations did not change. The degree of Ch saturation of bile, [BS+PL]/[Ch], decreased in each study, whether or not the original ratio indicated Ch supersaturation; in 3 of 5 studies, an initially supersaturated bile became unsaturated with Ch in response to breakfast. No significant changes were noted after lunch. During interruption of enterohepatic circulation (EHC), studies with radiolabeled bile acids indicated that the increased bile acid output in response to meals was secondary to increased recirculation of intestinal bile acids rather than to de novo bile acid synthesis. This mechanism may account for the adequate delivery of BS and for the decreased degree of Ch saturation of bile postprandially in cholecystectomized patients.