Differences in cholesterol oxidation and biosynthesis in liver of male and female rats

Abstract

Female rat liver mitochondria oxidized cholesterol-26-C¹⁴ and sodium pyruvate-2-C¹⁴ to C¹⁴O₂ to a much greater extent (per mg N) than did male rat liver mitochondria. Mitochondrial preparations from livers of castrated, estrogenized or castrated-estrogenized male rats all oxidized cholesterol-26-C¹⁴ to a greater extent than did liver preparations from normal male rats. No differences were observed in the oxidation of sodium octanoate-1-C¹⁴. The serum and liver cholesterol levels of the feminized rats were higher than those of the intact males. Biosynthesis of cholesterol from sodium acetate-2-C¹⁴ by male rat liver homogenates was significantly lower than biosynthesis by liver homogenates from normal female rats or gonadectomized rats of both sexes. The rate of biosynthesis from mevalonic acid-2-C¹⁴ by liver homogenates from castrated male rats was much higher than in homogenates of oophorectomized females or intact males or females. Differences in sex or gonadectomy had no effect on biosynthesis of fatty acids from sodium acetate-2-C¹⁴.