Which hormone is produced by the anterior pituitary and promotes milk production?

Prolactin is the hormone produced by the anterior pituitary gland that plays a key role in promoting milk production in the mammary glands. It is secreted primarily during pregnancy and after childbirth, stimulating the mammary tissues to develop and produce milk. This process is crucial for lactation, ensuring that a mother can feed her newborn. Prolactin levels rise in response to various signals, including the suckling of the infant, which further stimulates milk production.

In the context of the other hormones listed, oxytocin is involved in the milk ejection reflex but does not promote milk production, while relaxin is primarily associated with pregnancy and childbirth, preparing the body for labor. Follicle Stimulating Hormone (FSH) is involved in reproductive processes such as the development of eggs in ovaries and is not related to lactation. Thus, prolactin's specific role in milk production distinguishes it as the correct answer in this scenario.