[Progress in prolactin receptor research].

Prolactin (PRL) is secreted by lactotrophs in the anterior pituitary and some extra-pituitary tissues such as breast, lacrimal gland, uterus, thymus and spleen, etc. Since PRL is closely related to growth hormone (GH) and placental lactogens (PL), it has been broadly accepted that PRL, GH and PL are resulted from the duplication of an ancestral gene. PRL regulates hundreds of biological functions by endocrine, paracrine and autocrine manners.