Adult Sheep Blood Metabolizes Dihydrotestosterone to 5a-Androstane-3 a,17ß-diol and 5a -Androstane-3 ß, 17ß-diol

The metabolism of 5a-dihydrotestosterone by adult sheep blood was investigated. Erythrocytes contain 3a- and 3i1-hydroxysteroid dehydrogenase activities. The mean rate of reduction of 5a-dihydrotestosterone by erythrocytes established in 15-min incubations was 0·66 ± 0·36 (s.d.) I'mol ml- 1 erythrocytes h - 1 and at equilibrium after a 60-min incubation, 90·6 ± 5· I % of the substrate was reduced. The reduction of 5a-dihydrotestosterone was shown to be dependent upon extracellular glucose and the intracellular cofactor NADPH. The proportion of the two reduction products was determined at equilibrium after separation by paper partition. chromatography and favoured 5a-androstane-3a, 17i1-diol (96·0%) to 5a-androstane-3i1,17i1-diol (4 ·0%). The identities and proportions of the two products were confirmed by recrystallization procedures.