It is secreted by posterior pituitary along with ADH Pituitary extract was first used in labour in 1909.Vigneaud in 1963 separated oxytocin and ADH.Both are synthesized in supra optic and Para ventricular nuclei of hypothalamus and stored in nerve in neurohypophysis endings. It circulates in an unbound form cleared from maternal circulation by kidney and liver. Oxytocin was the first polypeptide hormone synthesized and in 1995 Nobel Prize in Chemistry was awarded for this to Vigneuad and co workers.