title: Inhibitory effect and interaction of stanozolol with pig testicular cytochrome P-450 (17 alpha-hydroxylase/C17,20-lyase).
abstract: The inhibitory effect of an anabolic steroid, stanozolol, on testicular microsomal cytochrome P-450 (17 alpha-hydroxylase/C17,20-lyase) (P-450(17 alpha/lyase] and the nature of the interaction were compared with those of other anabolic steroids, furazabol and mestanolone. Stanozolol markedly inhibited delta 16-C19-steroid synthesizing activity, 17 alpha-hydroxylase and C17,20-lyase activities, which were mediated by oxygenase activities of testicular microsomal cytochrome P-450(17 alpha/lyase). In addition, stanozolol was a competitive inhibitor of 17 alpha-hydroxylase (Ki = 6.31 microM) and C17,20-lyase (Ki = 1.30 microM) activities in the reconstituted enzyme system. The interaction of cytochrome P-450&17 alpha/lyase) with stanozolol induced a type I difference spectrum (peak at 387 nm and trough at 418 nm) with a dissociation constant (Ks) of 1.47 microM.
authors: S
authors: S
authors: Nakajin
authors: K
authors: K
authors: Takahashi
authors: M
authors: M
authors: Shinoda
mesh_terms: D000732:Androstanols / Q000494:pharmacology; D000818:Animals; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D013196:Dihydrotestosterone / Q000494:pharmacology / Q000031:analogs & derivatives; D066298:In Vitro Techniques; D008297:Male; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology; D013197:Stanozolol / Q000494:pharmacology*; D013552:Swine; D013737:Testis / Q000187:drug effects / Q000201:enzymology*
chemical_list: D000732:Androstanols; D065607:Cytochrome P-450 Enzyme Inhibitors; D013196:Dihydrotestosterone; C005025:furazabol; D013197:Stanozolol; D003577:Cytochrome P-450 Enzyme System; C008376:mestanolone