THE EFFECT OF A LIPIDE EXTRACT FROM THE POSTERIOR HYPOTHALAMUS AND OF PITRESSIN ON THE RELEASE OF ACTH FROM THE PITUITARY GLAND1

Abstract

The effect of a nonsaponifiable lipide extract of bovine posterior hypothalamus and of Pitressin on the corticotrophin secretion from the hypophysis was measured on the adrenal ascorbic acid content under different experimental conditions. In normal and in Nembutalized rats both substances caused an ascorbic acid depletion. This effect was abolished in hypophysectomized rats. Pharmacological blockade with morphine or hydrocortisone inhibited the effect of the lipide extract. Only morphine was able to prevent the adrenal activation by Pitressin. Electrolytic lesions destroying the median eminence, but not the hypophysial stalk, abolished the action of the lipide extract, whereas Pitressin was still highly active. It is concluded that the lipide extract requires the intactness of hypothalamic structures for its action, and that Pitressin contains the specific neurotransmitter.