Histochemical localization of 3 beta-hydroxysteroid dehydrogenase in the testes of chicken-pheasant hybrids

Histochemical studies on the activity of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) in the testes of adult chicken-pheasant hybrids and domestic fowl of similar age were carried out using dehydroepiandrosterone as the substrate. The reaction for 3beta-HSD was positive in the interstitial tissue and negative within seminiferous tubules of domestic fowl. In chicken-pheasant hybrids, a strong positive reaction for 3 beta-HSD was observed in the interstital tissue and within the seminferous tubules suggesting that, in hybrid testes, both Leydig cells and cells of seminiferous tubules may be capable of steroid biosynthesis. Since the plasma testosterone levels in these birds were found to be extremely low, it is hypothesized that either the chicken-pheasant hybrids do not release testosterone in sufficient amounts in the circulation or the type of steroid produced by the 3 beta HSD-positive cells may be different from testosterone that is required for the maintenance of normal fertility and the development of secondary sexual characteristics.