Effect of pinealectomy on annual testicular cycle of Indian chequered water snake, Natrix piscator.

Pinealectomy for 60 days (noted every month of the year), in the tropical Indian chequered water snake. Natrix piscator, caused inhibition of testicular growth during late progressive and active phases and retarded the rate of regression during regressive phase; during sexually inactive phase the testes remain partially active. The weight of the accessory sex organs, vas deferens, and kidney (along with the renal sex segment activity) followed the same pattern as that of the testes. Thus, it may be concluded that the pineal gland of this ophidian participates in the regulation of seasonal testicular cycle, probably via the hypothalamo-hypophyseal axis, and hence the effects of pinealectomy are seasonal and a reproductive phase-dependent phenomenon.