Metabolism of 4-C14-cholesterol in the isolated perfused rat liver

Abstract

The influence of the mode of administration on the distribution and oxidation of 4-C¹⁴-cholesterol in the isolated perfused rat liver has been studied. When labeled cholesterol was added to the perfusate as an emulsion with Tween 20 only about 1% of the labeled liver cholesterol was oxidized to bile acids. Approximately the same oxidation (1–2%) was obtained in perfusions of livers from animals injected with emulsions of 4-C¹⁴-cholesterol 1 hr before operation. When livers were perfused with blood withdrawn from animals injected with emulsions of 4-C¹⁴-cholesterol 24 hr prior to sacrifice the amount of labeled liver cholesterol converted to bile acids was about 10%, i.e., five to ten times more than in the above-mentioned sets of experiments, indicating the advisability of using physiological solutions of cholesterol rather than artificial emulsions. The main labeled acidic products were identified as cholic and chenodeoxycholic acid. The only labeled product isolated from ethanol extracts of the liver was found to be identical with cholesterol.