[Increase of cholesterol hydroxylation in rat liver as a result of induction of microsomal enzymes]

Abstract

A possibility to increase 7alpha-hydroxylation of 4-14C-cholesterol was studied in vitro, using microsomal enzymes from rat liver tissue, under effect of such inductors of these enzymes as 5-ethyl-5-phenyl barbituric acid (phenobarbital), pregnenolone-16alpha-carbonitrile, 16-dehydropregnenolone, 3-acetate-16alpha-isothiocyanogen pregnenolone. These inductors were administered per os within 5 days as an aqueous suspension, stabilized with Tween 80 at a dose 50 mg/kg daily; ethyl ester alpha-(p-chlorophenhydroxy)-isobutyric acid (klofibrate "Miskleron*) was administered at a dose of 150 mg/kg daily within 5 days. All the inductors studied increased the activity of cholesterol 7alpha-hydroxylase: pregnenolone-16alpha-carbonitrile--by 50%, 16-dehydropregnenolone--by 80%, 3-acetate-16alpha-isthiocyanogen pregnenolone--by 110% and phenobarbital--by 200%. Klofibrate did not affect the intensity of the cholesterol hydroxylation.