Metabolism of two hydroxy-7-oxocholanic acids in isolated perfused rat liver

The metabolism of 7-oxolithocholic acid and 7-oxodeoxycholic acid in isolated perfused rat livers was compared. The metabolites extracted from the bile of perfused livers were analysed by gas chromatography. The amount of bile acids excreted in bile was greater after infusion with 7-oxolithocholic acid than with 7-oxodeoxycholic acid. When 7-oxolithocholic acid was infused almost all of the bile acids excreted in bile were taurine conjugates; with 7-oxodeoxycholic acid about 10 percent remained unconjugated. 7-Oxolithocholic acid was more susceptible to reduction than 7-oxodeoxycholic acid. 7-Oxolithocholic acid was preferably reduced to 7 beta-hydroxy rather than to 7 alpha-hydroxy metabolites. In contrast, 7-oxodeoxycholic acid was reduced predominantly to the 7 alpha-hydroxy rather than to the 7 beta-hydroxy metabolite.