Final answer:
Prolactin (PRL) is a hormone that stimulates milk production in mammary glands.
Step-by-step explanation:
Prolactin (PRL) is a hormone produced by the anterior pituitary gland that stimulates milk production in mammary glands. It is responsible for the establishment and maintenance of breast milk supply. Prolactin levels are regulated by the hypothalamic hormones prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH).