title: Effects of treatment with clofibrate, bezafibrate, and ciprofibrate on the metabolism of cholesterol in rat liver microsomes.
abstract: The effects of treatment of rats with clofibrate, bezafibrate, and ciprofibrate on the hepatic metabolism of cholesterol were studied in rat liver microsomes. HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase activity, regulating cholesterol biosynthesis, was unaffected by clofibrate and ciprofibrate and slightly decreased (20%) by bezafibrate. Also cholesterol 7 alpha-hydroxylase activity, governing bile acid biosynthesis, was unaffected by clofibrate and was reduced by 25-30% in the two other groups of rats. A major new finding was that all three fibric acid derivatives reduced ACAT (acyl-coenzyme A:cholesterol acyltransferase) activity, catalyzing the esterification of cholesterol, by 50-70%. The hepatic content of free and esterified cholesterol was determined in the bezafibrate-treated rats. The concentration of microsomal cholesteryl ester was about 60% lower in the treated rats compared to the controls whereas the concentration of total cholesterol was unchanged.
authors: Department of Medicine, Karolinska Institutet, Huddinge University Hospital, Sweden.
authors: D
authors: D
authors: Ståhlberg
authors: B
authors: B
authors: Angelin
authors: K
authors: K
authors: Einarsson
mesh_terms: D000818:Animals; D001629:Bezafibrate / Q000494:pharmacology; D002784:Cholesterol / Q000378:metabolism*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism; D002994:Clofibrate / Q000494:pharmacology; D002995:Clofibric Acid / Q000494:pharmacology; D058607:Fibric Acids; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D000960:Hypolipidemic Agents / Q000494:pharmacology*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D002785:Sterol O-Acyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D058607:Fibric Acids; D000960:Hypolipidemic Agents; D002995:Clofibric Acid; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; D002790:Cholesterol 7-alpha-Hydroxylase; D002785:Sterol O-Acyltransferase; C019304:ciprofibrate; D002994:Clofibrate; D001629:Bezafibrate