- A protein hormone of the anterior lobe of the hypophysis that stimulates the secretion of milk and possibly, during pregnancy, breast growth. SYN: galactopoietic hormone, lactation hormone, lactogenic hormone, lactotropin, mammotropic factor, mammotropic hormone. [pro- + L. lac, lact-, milk, + -in]
* * *pro·lac·tin prō-'lak-tən n a protein hormone of the adenohypophysis of the pituitary gland that induces and maintains lactation in the postpartum mammalian female abbr. PRL called also luteotropic hormone, luteotropin, mammotropin
* * *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. In both sexes excessive secretion of prolactin gives rise to abnormal production of milk (galactorrhoea).
* * *pro·lac·tin (PRL) (Prl) (pro-lakґtin) [pro- + L. lac milk] an anterior pituitary hormone with 198 amino acids, molecular weight 23,000, which stimulates and sustains lactation in postpartum mammals after the mammary glands have been prepared by other hormones such as estrogens, progesterone, growth hormone, corticosteroids, and insulin. It also stimulates formation of â€œmilkâ€ in the crop sac of birds such as pigeons and doves (an action formerly used for bioassay), is luteotropic in certain mammals, and has many other effects, including essential roles in the maintenance of immune system functions. Called also lactogen, luteotropin, and lactogenic or luteotropic hormone.
Medical dictionary. 2011.