title: Species differences in 5 alpha-androstane-3 beta,17 beta-diol hydroxylation by rat, monkey, and human prostate microsomes.
abstract: The 6 alpha-, 7 alpha-, and 7 beta-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol by rat prostate microsomes appears to be catalyzed by a single, high-affinity cytochrome P450 enzyme. In the present study we have examined the hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol by prostate microsomes from cynomolgus monkeys and from normal subjects and patients with benign prostatic hyperplasia. Our results suggest that although rat, monkey, and human prostate microsomes catalyze the 6 alpha-, 7 alpha-, and 7 beta-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol, these pathways of oxidation in monkeys and humans are not catalyzed by a single cytochrome P450 enzyme. The ratio of the three metabolites was not uniform among prostate microsomal samples from individual humans or monkeys. The 6 alpha-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol varied independently of both the 7 alpha- and 7 beta-hydroxylation, which varied in unison. The 6 alpha-, 7 alpha-, and 7 beta-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol by monkey prostate microsomes appeared to be differentially affected by in vivo treatment of monkeys with beta-naphthoflavone or dexamethasone. Treatment of a monkey with dexamethasone appeared to cause a 2.5-fold increase in both the 7 alpha- and the 7 beta-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol without increasing the 6 alpha-hydroxylation. The 7 alpha- and 7 beta-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol by human and monkey prostate microsomes, but not the 6 alpha-hydroxylation, was inhibited by antibody against rat liver NADPH-cytochrome P450 reductase. Similarly, the 7 alpha- and 7 beta-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol by human prostate microsomes, but not the 6 alpha-hydroxylation, was markedly inhibited (greater than 85%) by equimolar concentrations of the imidazole-containing antimycotic drugs ketoconazole, clotrimazole, and miconazole. These results suggest that the 7 alpha- and 7 beta-hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol by monkey and human prostate microsomes is catalyzed by a cytochrome P450 enzyme, whereas the 6 alpha-hydroxylation is catalyzed by a different enzyme which may or may not be a cytochrome P450 monooxygenase. The hydroxylation of 5 alpha-androstane-3 beta,17 beta-diol by prostate microsomes from normal human subjects was quantitatively and qualitatively similar to its hydroxylation by prostate microsomes from patients with benign prostatic hyperplasia.(ABSTRACT TRUNCATED AT 400 WORDS)
authors.affiliation: Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City 66160-7417.
authors.forename: B
authors.initials: B
authors.lastname: Gemzik
authors.forename: S
authors.initials: S
authors.lastname: Jacob
authors.forename: S
authors.initials: S
authors.lastname: Jennings
authors.forename: J
authors.initials: J
authors.lastname: Veltman
authors.forename: A
authors.initials: A
authors.lastname: Parkinson
mesh_terms: D015113:Androstane-3,17-diol / Q000378:metabolism*; D000818:Animals; D000906:Antibodies; D000935:Antifungal Agents / Q000494:pharmacology; D001571:Benzoflavones / Q000494:pharmacology; D002248:Carbon Monoxide / Q000494:pharmacology; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology; D006801:Humans; D006900:Hydroxylation; D008252:Macaca fascicularis; D008297:Male; D008861:Microsomes / Q000201:enzymology*; D009251:NADPH-Ferrihemoprotein Reductase / Q000037:antagonists & inhibitors / Q000276:immunology; D011467:Prostate / Q000201:enzymology* / Q000648:ultrastructure; D011470:Prostatic Hyperplasia / Q000201:enzymology; D051381:Rats; D013045:Species Specificity; D019324:beta-Naphthoflavone
chemical_list: D000906:Antibodies; D000935:Antifungal Agents; D001571:Benzoflavones; D065607:Cytochrome P-450 Enzyme Inhibitors; D015113:Androstane-3,17-diol; D019324:beta-Naphthoflavone; D003907:Dexamethasone; D002248:Carbon Monoxide; D003577:Cytochrome P-450 Enzyme System; D009251:NADPH-Ferrihemoprotein Reductase