THE MILK-EJECTING ACTIVITY OF EXTRACTS OF THE POSTERIOR PITUITARY GLAND

Abstract

The lactating sow milked mechanically has been used for the study of the hormones of the posterior pituitary gland. The van Dyke protein and du Vigneaud's high potency posterior lobe oxytocic polypeptide have been shown to possess milk-ejecting activity equivalent to their oxytocic activity. Commercial pressor preparations and du Vigneaud's highly purified vasopressin have milk-ejecting activity corresponding to a given pressor activity which is equivalent to one-fifth of the same number of oxytocic units.