prolaktin

Prolaktin is a peptide hormone produced mainly by lactotroph cells in the anterior pituitary gland. It circulates in the blood and stimulates milk production in the mammary glands after childbirth; it also has roles in reproduction and immune function, though these are less clearly defined in humans.

Secretion is primarily inhibited by dopamine from the hypothalamus; suckling and high estrogen during pregnancy relieve this inhibition, increasing prolaktin release. Other factors include stress, exercise, thyroid status, and certain drugs. Prolaktin levels are pulsatile and tend to rise with sleep and pregnancy.

Hyperprolaktinemia is the most common abnormality. In women it can cause galactorrhea, menstrual disturbances, and infertility; in men, reduced libido and infertility. Causes include physiological states (pregnancy, lactation), pituitary adenomas (prolaktinomas), hypothyroidism, kidney disease, and dopamine-blocking medications.

Diagnosis involves serum prolaktin measurement, often with repeat testing and consideration of macroprolaktin. MRI may be used if levels are high or to evaluate a pituitary tumor. Treatment targets the cause: dopamine agonists (cabergoline, bromocriptine) for prolaktinomas; adjusting medications for drug-induced hyperprolaktinemia.