Nutritional Status, Time of Day and Pinealectomy: Factors Influencing the Sensitivity of the Neuroendocrine-Reproductive Axis of the Rat to Melatonin

摘要: Afternoon but not morning injections of melatonin (Mel) resulted in significant 68, 50 and 20% reductions seminal vesicle, ventral prostate testicular weights, respectively, as compared with underfed controls. As the animals injected morning, reproductive organ weights underfed-pinealectomized rats were unaffected by afternoon Mel. Both pituitary serum prolactin levels significantly depressed receiving Mel afternoon; however, was ineffective when given either or to pinealectomized rats. These data indicate that there is a diurnal rhythm sensitivity undernourished which abolished pinealectomy.