Prolactin Hormones Effect Both Men and Women

The hormone prolactin is produced by the anterior pituitary. It is a single-chain protein with a lot of similarities to growth hormone. Prolactin's main function is the production on milk after childbirth but it also plays a role in the development and growth of breasts. Small amounts of the prolactin hormone are normally present throughout the bloodstream of both males and females. Dopamine, also known as prolactin inhibiting factor, limits the production of prolactin and keeps it under control. The dopamine binds to lactotroph receptors and obstructs the production and secretion of prolactin. Other hormones also contribute to the inhibition of prolactin secretion, including GRH, TRH, and vasoactive intestinal polypeptide.

Lactation, Breastfeeding, and Postpartum Weight Loss

Prolactin levels increase dramatically, 10 to 20 times higher, when a female becomes pregnant. Milk is produced after the baby is born, due to the combination of high levels of prolactin hormones and sudden drop in estrogen and progesterone hormones. Lactation is the process in which milk is secreted from the mammary glands through the nipples to provide nourishment for a newborn baby. If the woman breastfeeds, the prolactin hormone levels remain high, but if she chooses not to breastfeed, they will return to normal.

Within 72 hours of delivering the baby, the woman's body begins producing milk full-time. Stimulation to the nipples and mammary glands, during nursing encourages prolactin hormone release. Colostrum, a high-protein, low-fat substance full of antibodies, is produced for the first few days. During lactation, the woman's body adjusts to produce as much milk as the baby needs. The more the baby nurses, the more milk the mother's body will produce. The American Academy of Pediatrics recommends breastfeeding alone for the first six months, after which, new food may be introduced. They also recommend that breastfeeding continue for at least 12 months. Breastfeeding, exercise, and a healthy diet facilitate postpartum weight loss. After the baby has been weaned, the breasts may continue to produce milk for several additional months.

High Prolactin Hormone Levels

Hyperprolactinemia, the excessive secretion of prolactin hormones, is a common disorder in humans. Thyroid hormone supplement has been shown to lower prolactin levels. Hyperprolactinemia can be caused by a lack of menstrual cycles (amenorrhea), excessive secretion of milk (galactorrhea), some drug therapies, and prolactin-secreting tumors. Men with hyperprolactinemia typically show hypogonadism, decreased sperm production, lowered sex drive, and impotence. These men often show breast enlargement (gynecomastia), though they rarely produce milk.