Abstract
The effect of chronic intraventricular treatment with melatonin on release of interstitial cell-stimulating hormone (ICSH) from the pituitary was studied in adult male dogs. A single intraventricular administration of melatonin at the doses of 1 and 10mg caused a reduction of the pituitary ICSH activity 10 days after the injection. Concomitantly, there was depletion of plasma ICSH activity. Control injection of isotonic saline solution or 1.6% alcohol-isotonic saline solution did not significantly alter the ICSH activity in the pituitary and the plasma of intact animals. The results are in accord with the hypothesis that melatonin exerts an inhibitory action on the release of pituitary ICSH.
