The effect of cholestyramine on bile acid kinetics in healthy controls.

Serum lipids and the kinetics of the two primary bile acids, cholic acid (C) and chenodeoxycholic acid (CD), were studied in six normolipidaemic subjects before and during treatment with cholestyramine (12 g/day). After therapy, total serum and low-density lipoprotein cholesterol decreased by about 15%. These changes were accompanied by significant increases in the pool size, synthesis, and fractional turnover rate (FTR) of C and in the synthesis and FTR of CD. In spite of the enhanced formation of CD, the CD pool size decreased in all subjects, on average by more than 50%. The combined pool size of C and CD remained constant, but the mean total bile acid formation increased by a factor of 2.9. It is suggested that the different responses of C and CD, with an augmented contribution of C to the total amounts of bile acid produced, reflect an enhanced hepatic cholesterogenesis and, possibly, that C and CD to some extent originate from different cholesterol precursor pools.