A COMPARISON OF CERTAIN RESPONSES OF THE VASCULAR SYSTEM OF RATS AFTER THE ADMINISTRATION OF PROGESTERONE AND OESTROGEN

Abstract

SUMMARY The effects of progesterone and oestrogens on vascular responses to oxytocin were studied in female rats. Like oestrogens, progesterone caused the appearance of a pressor response to oxytocin, and throughout pseudopregnancy oxytocin acted as a pressor substance. The pressor response to oxytocin was the same, whether progesterone and oestrogen were given singly or together. Eserine abolished the pressor response to oxytocin of rats in natural oestrus or animals treated with an oestrogen, but did not eliminate the pressor response after progesterone.