Prolactin, also called luteotropic hormone, is a hormone that signals to a number of tissues within the body. It belongs to a class of hormones known as peptide hormones, and it's main function is to facilitate breast milk production and secretion--a process called lactation. Prolactin is released by a region of the brain called the pituitary gland, and then circulates in the bloodstream to signal to tissues. A number of conditions and factors can lead to high prolactin levels.
Pregnancy and Breastfeeding
A natural condition that leads to a high prolactin level is pregnancy, followed by breast feeding. During pregnancy, the breasts mature and begin to prepare for breastfeeding following the birth of the baby. Early in pregnancy, hormones such as estrogen promote the growth and expansion of breast tissue, leading to breast enlargement. After breast growth, other hormones, including prolactin signal for the maturation of milk-producing cells to facilitate lactation. Prolactin levels remain high after birth to allow for sustained lactation, then fall again upon cessation of breastfeeding. High prolactin levels during pregnancy and breastfeeding are normal, and not a cause for concern.
Antipsychotic Medication
Some medications, especially antispychotic medications can lead to high prolactin levels. Sustained used of these medications can lead to sustained high levels of prolactin, which can cause a number of deleterious side effects.
A study published in "The British Journal of Psychiatry" in 2004 reports that some long-term users of antipsychotic medications to treat schizophrenia experienced chronic excess prolactin that led to hypogonadism, a disease that causes hormone imbalance in females. The study also indicates that patients on these medications experienced a decrease in bone mineral density and an increased risk of osteoporosis due to excess prolactin.
Pituitary Tumors
Pituitary tumors may also lead to an increase in prolactin levels. Under normal conditions, the cells of the pituitary make and secrete prolactin corresponding to the body's needs. In the development of a pituitary tumor, the number of prolactin-secreting cells increases, which in turn increases the amount of prolactin secreted. Prolactin-secreting pituitary tumors are also called prolactinomas.
Women with prolactinomas may experience missed or irregular periods, as well as lactation not associated with pregnancy. Men with prolactinomas may experience erectile dysfunction and male breast growth, called gynecomastia. If the tumor progresses, men and women may develop vision problems or headaches as the tumor grows. Prolactinoma can be treated with surgery, drug therapy or radiation therapy.
