A STUDY OF THE EFFECT OF MELATONIN ON THE GONADS, THE OESTROUS CYCLE AND THE PINEAL ORGAN OF THE RAT

Abstract

ABSTRACT Daily injections of melatonin during 21 to 29 days in immature and adult albino rats exposed to normal light conditions (daily dose 30 μg or 150 μg melatonin) or to continuous light (daily dose 150 μg melatonin) did not affect gonadal weight or the oestrous cycle. After the same treatment the pineal parenchymal cells seemed morphologically normal and the size of their nuclei was not changed. Under normal day/night conditions, a daily dose of 30 μg or 150 μg melatonin did not alter the lipid content of the pineal parenchymal cells. Under continuous light, a daily dose of 150 μg melatonin was able to reverse to a slight extent the light-induced lipid depletion.