title: Inhibition of steroid 17 alpha-hydroxylase and C17,20-lyase in the human testis by epitestosterone.
abstract: Epitestosterone (17 alpha-hydroxy-4-androsten-3-one) inhibited competitively 17 alpha-hydroxylation of pregnenolone and subsequent C17,20-side chain cleavage of resulting 17 alpha-hydroxypregnenolone using microsomal preparations from the human testis. The inhibition constants for 17 alpha-hydroxylase and C17,20-lyase with 5-ene-precursors of C21-steroids were 96 and 12.4 mumol/l, respectively.
authors.affiliation: Institute of Endocrinology, Prague, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Bicíková
authors.forename: R
authors.initials: R
authors.lastname: Hampl
authors.forename: M
authors.initials: M
authors.lastname: Hill
authors.forename: L
authors.initials: L
authors.lastname: Stárka
mesh_terms: D000446:Aldehyde-Lyases / Q000037:antagonists & inhibitors*; D065607:Cytochrome P-450 Enzyme Inhibitors; D004845:Epitestosterone / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008297:Male; D013254:Steroid 17-alpha-Hydroxylase / Q000037:antagonists & inhibitors*; D013737:Testis / Q000201:enzymology*
chemical_list: D065607:Cytochrome P-450 Enzyme Inhibitors; D004845:Epitestosterone; D013254:Steroid 17-alpha-Hydroxylase; D000446:Aldehyde-Lyases