Abstract

Hormones with structural and functional similarities to the hormones of the anterior pituitary gland fall into two main categories, ie, proteins of the prolactin/growth hormone (PRL/GH) family, and glycoproteins. Anterior pituitary-like hormones are produced in the placenta by chorionic tissue, and so are normally found in the female during pregnancy. Placental lactogens, members of the PRL/GH family, support growth and development of mammary tissue in preparation for lactation. Chorionic gonadotropin is similar in structure to luteinizing hormone and supports the maintenance of early pregnancy. Chorionic gonadotropin is found in humans and lower primates, as well as in horses. Information on primary structure and commercial sources is provided when available.