[Interrelationship of the pineal body with the hypothalamo-hypophyseal complex. II. The effect of melatonin on the incorporation of H3-leucine in the anterior and medial hypothalamic nuclei of pinealectomized blinded rats].

A study was made of the effect of low doses of melatonin on the H3-leucine incorporation into the supraoptic, paraventricular, ventro-medial, and arcuate nuclei of the hypothalamus. Sexually mature blinded pinealectomized female rats were used in these experiments. Melatonin administered in a dose of 10 mug at 11 a.m. for 9 days inhibited the biosynthetic potential of the mentioned hypothalamic nuclei enhanced by extirpation of the epiphysis. Administration of melatonin at 11 p.m. in the same doses produced no effect on leucine incorporation.