Studies on 17β-hydroxysteroid dehydrogenase in immature mouse ovarian tissue

17β-hydroxysteroid dehydrogenase (EC 1.1.1.64) activity was studied in immature mice ovarian tissue. The substrates employed in this investigation were 4-androstene-3.17-dione (androstenedione) and oestradiol-17β. The products of the enzymic reaction. 17β-hydroxy-4-and rosten-3-one (testosterone) and oestrone respectively were identified by thin-layer chromatography, gas-liquid chromatography, mass spectrometry and derivative formation. The radiochemical purity was established by recrystallization to constant specific activity. For the reduction of androstenedione to testosterone NADPH was the electron donor whereas the oxidation of oestradiol-17β to oestrone utilized NADP⁺ as well as NAD⁺ as electron acceptor. Triphosphopyridine nucleotide was the preferred cofaetor for the latter reaction. The results of the present experiments demonstrate that the ovaries of immature mice devoid of corpora lutea are capable of converting androstenedione to testosterone and oestradiol-17β to oestrone indicating the presence of 17β-hydroxy steroid dehydrogenase in such tissue.