prolactin (lactogenic hormone; luteotrophic hormone; luteotrophin) A hormone produced by the anterior pituitary gland. In mammals it stimulates the mammary glands to secrete milk (see lactation) and the corpus luteum of the ovary to secrete the hormone progesterone. Secretion of prolactin is increased by suckling. In birds prolactin stimulates secretion of crop milk by the crop glands.

prolactin (lactogenic hormone) A protein hormone, secreted by the adenohypophysis (anterior pituitary), that initiates lactation in mammals and stimulates the production of progesterone by the corpus luteum.

prolactin (lactogenic hormone, luteotrophic hormone, luteotrophin) (proh-lak-tin) n. a hormone, synthesized and stored in the anterior pituitary gland, that stimulates milk production after childbirth and also stimulates production of progesterone by the corpus luteum in the ovary.