- an anterior pituitary polypeptide hormone that stimulates lactation by the mammary glands at parturition in mammals, the activity of the crop in birds, and in some mammalian species the production of progesterone by the corpus luteum.
- a gonadotrophic hormone secreted by the anterior lobe of the pituitary gland. In mammals it stimulates the secretion of progesterone by the corpus luteum and initiates and maintains lactation
