title: Biosynthesis of 16 alpha, 17 alpha-epoxy-4-androsten-3-one in rat liver microsomes.
abstract: 4,16-Androstadien-3-one was incubated with the microsomal fraction of male rat liver in the presence of a NADPH generating system and oxygen. The metabolites formed were extracted from the incubation medium and purified by thin-layer chromatography (tlc). Final identification was performed by combined gas liquid chromatography-mass spectrometry. Incubation of 4,16-androstadien-3-one resulted in the formation of a non-polar metabolite which proved to be 16 alpha, 17 alpha-epoxy-4-androsten-3-one. This epoxide is a shortlived intermediate which is rapidly hydrolysed by the microsomal epoxide hydratase to 16 beta, 17 alpha-dihydroxy-4-androsten-3-one. In order to increase the amounts of epoxide in the incubation mixtures, styrene oxide which is a potent inhibitor of the epoxide hydratase was added. Under these conditions, up to 8% of the 16-dehydro-steroid incubated was transferred to the 16 alpha, 17 alpha-epoxy-compound.
mesh_terms: D015113:Androstane-3,17-diol / Q000378:metabolism; D000734:Androstenediols / Q000378:metabolism; D000735:Androstenedione / Q000378:metabolism; D000736:Androstenes / Q000096:biosynthesis*; D000818:Animals; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D013058:Mass Spectrometry; D008862:Microsomes, Liver / Q000378:metabolism*; D051381:Rats
chemical_list: D000734:Androstenediols; D000736:Androstenes; D015113:Androstane-3,17-diol; D000735:Androstenedione; C028183:16,17-epoxy-4-androsten-3-one