Kinetics of cholesterol and bile acids in patients with cholesterol cholelithiasis.

The kinetics of cholesterol and bile acid was determined from a 10-week analysis of the biliary lipids after a single injection of labeled cholesterol in parallel with a conventional 1-week study of primary bile acid kinetics. Six healthy controls and 6 patients with cholesterol cholelithiasis were studied. Two of the 6 cholesterol cholelithiasis subjects had kinetic values that were very similar to the controls and the other 4 were significantly different. These 4 patients had significantly smaller primary bile acid pools and significantly lower fractional conversions of cholesterol to both primary bile acids, with concomitantly lower bile acid flux. No significant differences were obtained for the size of the rapidly miscible cholesterol pool, the fractional rate of loss and flux of biliary neutral sterol, and the fractional turnover of the primary bile acid pools. These kinetic data support the hypothesis that in some patients with cholesterol cholelithiasis there is defective conversion of cholesterol to bile acids.