Antigonadal Effect of Melatonin in Pinealectomized and Intact Male Hamsters

Abstract

Summary The administration of mela-tonin (12-150 μg/day) via subcutaneous Si-lastic capsules inhibited photic-induced testicular recrudescence to the same degree in both pinealectomized and intact hamsters. Melatonin (300 μg/day) also induced marked testicular regression in sexually mature intact and pinealectomized hamsters maintained on a photostimulatory LD 14:10 light cycle. The similar responses of pinealectomized and intact hamsters to melatonin treatment indicate that the effects of exogenous melatonin are not mediated via the pineal gland.