Hyperprolactinemia
Prolactin is a hormone secreted by the anterior pituitary gland which is critical to the initiation and maintenance of lactation (breast milk production). Prolactin’s release is controlled by the actions of an inhibitory neurohormone, dopamine. If dopamine secretion is reduced then prolactin levels may rise inappropriately. Normal plasma prolactin levels are 5-27 ng/ml. Peak prolactin secretion occurs between 5-7 am. The lowest levels are in mid morning. Physiologic causes of elevation include stress, venipuncture, breast stimulation, and/or physical examination. One elevated value should always be rechecked in the midmorning.
Other causes of prolactin elevation include: activation of a neuroendocrine circuit (chest incisions, shingles of the chest, spinal cord injury or lesions, and breast surgery); decreased dopamine (use of phenothiazines, tranquilizers, opiates, antidepressants); pituitary microadenoma (nonmalignant tumors of the pituitary gland less than 1 cm), pituitary macroadenoma or other tumor (greater than 1 cm); hypothyroidism (hypothyroidism causes the release of thyroid stimulating hormone (TRH) which promotes prolactin production; and, renal failure. Prolactin levels are measured in women with amenorrhea (absence or cessation of menses), galactorrhea (breast milk secretion), and infertility.
Hyperprolactinemia is a relatively common cause of amenorrhea, galactorrhea, and infertility. There are very effective medical treatments for hyperprolactinemia which usually resolve these disorders. Your reproductive endocrinologist will detect the cause of the elevation. An MRI of the pituitary gland may be part of the evaluation.
