True about oxytocin are all except -

Ans. is 'd' i.e., Causes contraction of lower segmentOxytocino Oxytocin is a nonapeptide, synthesized predominantly in the paraventricular nucleus of the hypothalamus along with its binding protein neurophysin II. Oxytocin has following physiological actions : -Uterus : - It increases the force and frequency of uterine contraction. Estrogens sensitize the uterus to oxytocin, while progestins decrease the sensitivity. The increased contractility is restricted to the fundus and body, lower segment is not contracted, may even be relaxed at term.Breast: - Oxytocin contracts myoepithelium of mammary alveoli and forces milk into bigger sinusuids - Milk ejection or milk letdown reflex.o Oxytocin secretion is inhibited by sympathetic discharge and circulating catecholamines, by pain and enkephalins, by emotional stress, especially fear, and by alcohol.