Prolactin (PRL, Milk Hormone, Stress Hormone) Excess


What is prolactin (PRL, milk hormone)?

Prolactin is a hormone secreted from the pituitary gland located in the middle region of the brain. It is written as PRL for short.

What should be the normal values ​​of prolactin (PRL) hormone?

Although the hormone prolactin changes during the menstrual cycle in women, its value is approximately 13-15 µg/L. Values ​​above 20 µg/L (ng/mL) are generally considered abnormally high in women of reproductive age. Prolactin level is a hormone with the highest reference value of 25. If it rises above this reference value, the Prolactin level is considered excessively high and should be examined and treated. is the case.

As the months progress in pregnancy, the level of prolactin hormone also increases and reaches values ​​far above normal.
In men, it is usually found in values ​​ranging from 6-10 µg/L.

What are the effects of prolactin (PRL) hormone?

The hormone prolactin has a wide variety of effects and tasks in the male and female body. Some of these are those:
– Ensuring milk production in the breasts in women
– Has duties related to sexual desire and desire.
– It has effects on sperm production stages in men

Symptoms of high prolactin (PRL, milk hormone):

Prolactin elevation is called “hyperprolactinemia”.
– Anovulation and menstrual irregularity: menstrual irregularity, Sometimes it can cause a lack of menstruation for long months.
– It may cause milk or liquid to come from the breasts in women who are not pregnant or puerperal, and who do not breastfeed. This is called galactorrhea.
There may be tenderness and pain in the breasts.
– High prolactin can cause sexual reluctance in women.
– May cause dryness in the vagina and pain in intercourse
– hot flashes, irritability
– Low estrogen and testosterone hormones,
– bone loss (osteoporosis),
– In men, high prolactin hormone can cause symptoms such as enlargement of the breasts (gynecomastia), sexual reluctance, and inability to get an erection.
– Vision problems can occur in both sexes.

Diagnosis (diagnosis):

Prolactin hormone value can be determined by the blood test, and the high or low prolactin hormone level can be determined. In the next step, some other hormone assays or brain examination may be required to investigate the cause.
Presence of adenoma in the pituitary gland in the brain is investigated if the prolactin value is very high (higher than 100 µg/L), Pituitary MRI should be studied to show pituitary adenoma.
Low thyroid hormone can cause prolactin elevation. Therefore, thyroid (goiter) hormones should be evaluated.
– Drugs that may cause the patient to increase prolactin,
-psychiatric problems (prolactin increases in stress)

Causes of high prolactin (PRL):

* Physiological causes of prolactin hormone elevation:
– pregnancy
– Breast-feeding
– Sexual intercourse, touching the nipples
– Exercise
– Stress
– Sleep

* Drugs that cause prolactin hormone elevation:

– Dopamine receptor antagonists and dopamine synthesis inhibitors
– Antipsychotic drugs
– Opiate drugs
– Aticonvulsant drugs (epilepsy drugs)
– Some antihypertensive drugs
– Some antihistamine drugs
– Estrogen-containing drugs (As estrogen is found in low milk in birth control pills, it does not usually cause prolactin elevation.)

* Diseases that cause prolactin hormone elevation:

– Conditions that cause damage to the hypothalamus-pituitary axis: Causes such as tumor, trauma, infiltration. Prolactin rises because they inhibit inhibition by dopamine from the hypothalus to the pituitary.
– Adenomas formed in the pituitary: Prolactinoma (lactotropic adenoma, macroadenoma, microadenoma)
– Some systemic and chronic diseases
– Acromegaly
– Cushing’s disease
– Hypothyroidism (low thyroid hormone)
– Chronic kidney failure
– Bronchogenic carcinoma
– Sarcoidosis
– Serious trauma to the chest wall: It causes an increase in the hormone prolactin, similar to the neural mechanism in breastfeeding.

Idiopathic hyperprolactinemia:

In some patients with mild prolactin (milk hormone, prl) elevation, a cause cannot be found despite all investigations, this situation is called idiopathic hyperprolactinemia. The PRL value in idiopathic hyperprolactinoma is usually in the range of 20 -100 ng/mL (mcg/L).

Does high prolactin (milk hormone) prevent pregnancy?

Since high prolactin prevents ovulation (ovulation), it can prevent pregnancy. In this case, first of all, it is necessary to investigate the cause and determine the treatment method according to the results.

Treatment of high prolactin (PRL, milk hormone):

Treatment for the cause of prolactin elevation is required.
At high levels of prolactin hormone (milk hormone), drug treatments called dopamine agonists (broocryptine, cabergoline) are applied.
Sometimes this surgery is performed if there is a large adenoma in the pituitary gland that causes prolactin elevation. These conditions should be evaluated by a neurosurgeon. During each type of treatment, the blood prolactin hormone level is monitored at regular intervals.


A decrease in the level of prolactin hormone may occur. It is usually caused by dopamine, antiparkinson drugs, pathologies related to the pituitary gland (Sheehan’s syndrome), pituitary tumors, head trauma, some infections, infiltrative diseases. In women, the main symptom is the absence of milk from the breasts after childbirth.

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