Influence of pineal gland on spermatogenesis of toad (Bufo melanostictus).

The relationship between the pineal gland and testes of the toad was investigated in breeding and hibernating seasons. Pinealectomy increased spermatogenesis in hibernating toads but it failed to exert any effect during the breeding season. The pineals were found to be active during hibernation and atrophied in the breeding season. It is speculated that the cyclic pineal activity might be responsible for the seasonal variation of spermatogenesis in the toad.