Localization of 5-3 - and 17 -hydroxysteroid dehydrogenase activity in the efferent ducts, epididymis and vas deferens of the rabbit, hamster and marmoset monkey

Abstract

The presence and distribution of .DELTA.5-3.beta.-hydroxysteroid dehydrogenase (.DELTA.5-3.beta.-HSD: EC 1.1.1.51) and 17.beta.-hydroxysteroid dehydrogenase (17.beta.-HSD: EC 1.1.1.51) were studied histochemically in the excurrent ducts of the rabbit, hamster and marmoset monkey. Dehydroepiandrosterone (DHEA) and testosterone were used as substrates for .DELTA.5-3.beta.-HSD and 17.beta.-HSD, respectively, while phenanthroline monohydrate was used to eliminate non-specific staining due to other tissue dehydrogenases. The rabbit possessed least enzyme activity, which was confined to tubules in the middle segment of the epididymis. Enzyme activity was demonstrable throughout the excurrent ducts of the hamster and marmoset, with maximal staining occurring in the middle segment of the epididymis in both species. The region of maximum activity of hydroxysteroid dehydrogenase is where spermatozoa first develop their fertilizing capacity.