Effect of pinealectomy on the histology of the adrenocortical homologue and plasma cortisol level in the Indian catfish, Heteropneustes fossilis (Bloch).

In Heteropneustes fossilis, the adrenocortical cells were highly active, hypertrophied, and degranulated after 15 and 30 days of pinealectomy in spawning/postspawning phase. Besides, several cells had undergone pycnotic changes in the 30-day group. The plasma cortisol level increased significantly (P less than 0.05) in the pinealectomized fish in comparison to those of the sham pinealectomized and unoperated control fish. The increase was higher in the 15-day group than in the 30-day-pinealectomized group. The results suggest that the pineal organ exerts an inhibitory influence on the activity of the adrenal in the catfish.