Effect of pinealectomy on testosterone, estradiol-17 beta, esterone, and 17 alpha-hydroxyprogesterone levels during the annual reproductive cycle in the freshwater catfish, Clarias batrachus.

Abstract

The present study examines the relationship of the pineal gland to gonadal activity during the annual reproductive cycle in the freshwater catfish Clarias batrachus. The hormonal profiles of testosterone, estradiol-17 beta, estrone, and 17 alpha-hydroxyprogesterone along with the gonadosomatic index (GSI) were monitored to assess the effect of pinealectomy. Pinealectomy appeared to accelerate the gonadal development from January to May. Removal of pineal prior to the start of gonadal recrudescence (January and February), induced initiation of ovarian recrudescence earlier than scheduled in nature. On the other hand pinealectomy during the vitellogenic phase (May to June) reduced the gonadal activity, suggesting the stimulatory role of pineal on gonads. During the remaining period of July to December (postvitellogenic and early resting phase) pinealectomy had no effect on gonadal activity. Thus, in this species the pineal gland during the annual reproductive cycle appears to have either inhibitory, stimulatory, or no effect on gonadal physiology depending upon the sexual conditions.