How does prolactin affect the body?
Prolactin is produced in the pituitary gland and normally rises sharply during pregnancy and breastfeeding, ensuring milk production. Its secretion is restrained by dopamine coming from the hypothalamus, so anything that disrupts this connection leads to an increase in the hormone. Excess prolactin suppresses the production of gonadotropins that control the ovaries and testicles: follicle maturation and ovulation are disrupted, estrogen levels in women and testosterone in men decrease. Long-term lack of sex hormones further worsens bone health, increasing the risk of osteoporosis.
- Synthesized in the pituitary gland, inhibited by dopamine
- Normally high during pregnancy and lactation
- Suppresses ovulation and the production of sex hormones
- Reduces libido and fertility
- Long-term excess worsens bone health
Reasons for the increase
Physiological increases occur during pregnancy, feeding, stress, physical activity, sleep, after sexual intercourse and stimulation of the nipples - this is why preparation for analysis is so important. Medicinal causes are very common: prolactin is increased by antipsychotics, some antidepressants, antiemetics, blood pressure medications and estrogens. Among the diseases, the leading place is occupied by prolactinoma, a benign tumor of the pituitary gland, as well as primary hypothyroidism, in which the increase in prolactin goes away after normalization of thyroid function. Less commonly, the cause is chronic renal failure and damage to the pituitary stalk.
- Prolactinoma and other pituitary tumors
- Taking antipsychotics, antidepressants, antiemetics
- Primary hypothyroidism
- Chronic renal failure
- Stress, physical activity, nipple stimulation
- Cirrhosis of the liver
- Macroprolactinemia is a laboratory phenomenon
Symptoms in women and men
In women, cycle disorders come to the fore: prolongation of intervals, rare menstruation or their complete cessation, as well as difficulties in becoming pregnant due to lack of ovulation. Approximately some patients experience colostrum discharge from the nipples, which can be scanty and noticeable only with pressure. In men, the symptoms are less obvious, so the diagnosis is made later: libido and potency decrease, sperm count decreases, and the mammary gland may enlarge. With a large pituitary tumor in both sexes, headache and loss of lateral visual fields are added.
- Infrequent or absent periods
- Lack of ovulation and infertility
- Nipple discharge outside of pregnancy
- Decreased libido
- In men - decreased potency and enlarged mammary glands
- Headache and blurred vision with a large tumor
- Decreased bone density over a long period of time
How to get examined correctly
Blood is donated in the morning, on an empty stomach or a few hours after a light breakfast, in a calm state, avoiding physical activity, sexual intercourse and nipple stimulation the day before, and preferably after 15–20 minutes of rest in the laboratory. The diagnosis is made when an increase is confirmed in repeated tests. Be sure to check TSH, since hypothyroidism is a common and completely removable cause. With a moderate increase without symptoms, macroprolactin is determined: this is a biologically inactive form of the hormone that overestimates the result and does not require treatment. MRI of the pituitary gland with contrast is prescribed if there is a persistent significant increase without any other reason.
- Prolactin in the morning, at rest, with proper preparation
- Retest for confirmation
- TSH and free T4
- Macroprolactin with a moderate increase
- Pregnancy test for women
- MRI of the pituitary gland with contrast if indicated
- Examination by an ophthalmologist with assessment of visual fields
Treatment
The tactic depends on the reason. If prolactin is elevated due to medication, the doctor who prescribed the drug decides on a replacement - it is dangerous to stop antipsychotics and antidepressants on your own. With hypothyroidism, it is enough to compensate for the function of the thyroid gland, and prolactin decreases on its own. For prolactinoma, the basis of treatment is dopamine agonists: they not only normalize the hormone, but also reduce the size of the tumor, so surgery is rarely required - in cases of drug resistance, intolerance or vision threatening. Treatment is long-term, with monitoring of prolactin levels and, in case of tumor, repeated MRIs. Asymptomatic macroprolactinemia does not require treatment.
- Replacing the drug that caused the increase, the doctor decides
- Compensation for hypothyroidism
- Dopamine agonists for prolactinoma
- Prolactin control and repeat MRI
- Surgery for treatment resistance or vision hazard
- Observation for macroprolactinemia
- Pregnancy planning under the supervision of an endocrinologist
