Effect of endosulfan (thiodan) on vitellogenesis and its modulation by different hormones in the vitellogenic catfish Clarias batrachus.
This programme was planned in order to study the reproductive dysfunction caused by endosulfan in the fish Clarias batrachus with special reference to vitellogenesis. Vitellogenin was measured by radioimmunoassay. Endosulfan caused a drastic reduction in the plasma vitellogenin which was partially reversed by estradiol-17 beta (E2) in intact and ovariectomized fish. Hormones in combination were more effective than any single hormone in overcoming the impact of endosulfan. Triiodothyronine (T3), ovine luteinizing hormone releasing hormone (oLHRH) were effective in minimizing the effect of endosulfan whereas cortisol (F) and ovine somatotropic hormone (oStH) did not reduce the effect of endosulfan. Amongst the combined hormone treatments, E2 + oLHRH and E2 + T3 were the most potent in overcoming the effect of endosulfan on vitellogenesis.