Comparative effects of chenodeoxycholic acid and ursodeoxycholic acid on lipid synthesis in rat liver

Chenodeoxycholic and ursodeoxycholic acids reduce significantly the hepatic synthesis of lipids in rats. The present study has been carried out using (1-14C)acetate and evaluating its incorporation into different lipidic fractions of the liver by thin-layer radiochromatography. Ursodeoxycholic acid proved to be more active than chenodeoxycholic acid: in addition to a significant decrease of the hepatic incorporation of the acetate into cholesterol and triglycerides an increase of the hepatic incorporation of the acetate into phospholipids has been observed. The exogenous administration of bile acids diminishes the hepatic synthesis of cholesterol and therefore its biliary excretion; it enriches the bile acid and phospholipid pool in the liver and bile. By this way the action of bile acids establishes in the liver a condition which induces such an increase of availability of mixed micelles in the bile as to make it unsaturated in cholesterol.