Effect of Alcohol on Release of Oxytocin

Abstract

IT is known from the work of van Dyke and Ames¹ that previously administered ethanol blocks the release of antidiuretic hormone (ADH) in response to acetylcholine. Furthermore, during ethanol anæsthesia antidiuretic activity can be detected neither in the blood from the head nor in the urine, and injection of hypertonic saline into the carotid artery does not produce any significant antidiuretic response². It was found of interest to investigate the effect of ethanol also on the pituitary release of oxytocin. Since assay methods for oxytocin in blood are difficult and rather insensitive, it was found best to study the effect on the puerperal uterus of oxytocin released by suckling in the milk let-down reflex. The post-partum uterus of the rabbit is extremely sensitive to oxytocin, the threshold dose on the first post-partum day, being about 0.03 mu. oxytocin intravenously per kg body-weight³. As is the case in the human, suckling of the young produces a strong oxytocic response on the uterus during the first days after delivery in the rabbit.