An enzyme-histochemical study concerning the localization of steroid glucuronide production in the reproductive organs of African catfish, Clarias gariepinus

Abstract

In ovaries of the African catfish, Clarias gariepinus, uridine diphosphoglucose dehydrogenase (UDPGD) and 3β-hydroxysteroid dehydrogenase (3β-HSD) appear in the granulosa of post-ovulatory follicles. In testes, both enzymes are present in interstitial cells. The combined presence of UDPGD and 3β-HSD points to the formation of steroid glucuronides at these sites. Interstitial cells between the tubules of the seminal vesicle also show 3β-HSD activity, both in captive fish and fish from nature. However, in these interstitial cells UDPGD activity was restricted to a few cells in the seminal vesicle of fish from nature. The latter enzyme was furthermore demonstrated in the epithelium of the seminal vesicle tubules, its activity being weaker in captive fish. Thus, in the seminal vesicle, glucuronidation of steroids may take place in interstitial cells, and it cannot be excluded that this process can also take place in the epithelium of the tubules.