title: Dual regulation of 21-hydroxylase activity by sex steroid hormones in rat hepatocytes.
abstract: In the rat liver, cytochrome P450 catalyzes the hydroxylation of steroid hormones. The expression and activity of some P450 isozymes are regulated by sex steroid hormones. Steroid 21-hydroxylase activity in rat liver is provided mainly by CYP2C6. We studied the regulation of 21-hydroxylase activity by sex steroid hormones in rat primary hepatocyte culture. We added estrogens (estrone, estradiol, estriol) and androgens (testosterone, dihydrotestosterone), (ranging from 10(-9) to 10(-5)M) to the culture. The 21-hydroxylase activity was stimulated by estrogens and was suppressed slightly by androgen in a dose-related manner. The results of our studies demonstrated that sex steroid hormones act differently on 21-hydroxylase activity in rat hepatocytes and, thus, support the hypothesis that the extra-adrenal production of deoxycorticosterone from circulating progesterone is increased during pregnancy by the massive presence of estrogens.
authors.affiliation: Department of Pediatrics, Hamamatsu University School of Medicine, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Endoh
authors.forename: H
authors.initials: H
authors.lastname: Natsume
authors.forename: Y
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D004967:Estrogens / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013255:Steroid 21-Hydroxylase / Q000378:metabolism*
chemical_list: D000728:Androgens; D004967:Estrogens; D013255:Steroid 21-Hydroxylase