Which hormone is known to stimulate the milk production in mammals?

Prolactin (PRL) is the hormone responsible for stimulating milk production in mammals. It is produced by the anterior pituitary gland and plays a crucial role in lactation. During pregnancy and after childbirth, prolactin levels increase significantly to prepare the mammary glands for milk production. This hormone not only promotes the development of the mammary glands but also signals the body to produce milk post-delivery in response to the infant's suckling.

Other hormones listed, such as luteinizing hormone, follicle-stimulating hormone, and melanocyte-stimulating hormone, serve different functions in the body's endocrine system and are not directly involved in the process of milk production. For instance, luteinizing hormone and follicle-stimulating hormone are more related to regulating the reproductive system, while melanocyte-stimulating hormone is associated with pigmentation and other roles unrelated to lactation.