EFFECT OF MELATONIN AND 5-HYDROXYTRYPTAMINE ON ALDOSTERONE AND CORTICOSTERONE PRODUCTION BY ADRENAL GLANDS OF NORMAL AND HYPOPHYSECTOMIZED RATS

Abstract

SUMMARY: The effects of subcutaneous injections of melatonin (50, 100 and 200 μg./100 g. body weight) and 5-hydroxytryptamine (100, 200 and 400 μg./100 g.) on the production of aldosterone and corticosterone by the adrenal glands of intact and hypophysectomized adult male rats were investigated. Melatonin increased the production of corticosterone significantly and depressed simultaneously the production of aldosterone. In the hypophysectomized rats, melatonin was without effect. 5-Hydroxytryptamine increased the production of corticosterone but did not change that of aldosterone. The effect of 5-hydroxytryptamine on corticosterone production was abolished by hypophysectomy. The possibility of the existence of a pituitary-dependent aldosterone-inhibiting mechanism is discussed.