Prolactin is a hormone produced by the pituitary gland, located at the base of the brain. It plays a crucial role in regulating milk production in nursing mothers. Prolactin levels increase during pregnancy and breastfeeding, helping to ensure that infants receive adequate nutrition. In addition to its role in lactation, prolactin also influences various functions in both men and women, including reproductive health and immune system regulation. Abnormal levels of prolactin can lead to health issues, such as infertility or irregular menstrual cycles in women and reduced libido in men.