Endocrinology · 1966 · 20 citations · 0 references
Life SciencesAnimal SciencesEndocrinologyExcretionReproductive EndocrinologySteroid BiochemistryAndrogen PhysiologyGonadal HormonesGonadal Steroid HormonesGonadal SteroidogenesisSteroid Hormone BiochemistrySteroid MetabolismAndrogen MetabolismAndrogen MetabolitesFaecal Steroid ExcretionFecal Steroid ExcretionGonadal Steroid BiochemistryGonadal Steroid MetabolismRadioactivity MeasurementSpecific Activity Determination
A bovine male castrate (steer) was injected subcutaneously with 120 mg of testosterone- 4-14C (385 μc). In the first 24 hr radioactivity equivalent to 15 mg of testosterone-14C was excreted in fecal metabolites, all of which appeared in the nonconjugated state. Two of at least 6 steroid metabolites were identified. Epitestosterone- 14C (17α-hydroxyandrost-4-en-3-one) accounted for 37% of the 14C excreted and was isolated in crystalline form. Its specific activity was approximately half that of the injected testosterone-14C. A new metabolite, 17α-hydroxy-5β-androstan-3-one, accounted for 17% of the excreted radioactivity. (Endocrinology78: 907, 1966)