What is prolactin?

Prolactin plays a very important role in the life of both men and women; therefore, its levels must be monitored occasionally.

What is prolactin? Prolactin is a single-chain peptide hormone closely related to that of growth. It is secreted by the so-called lactotropic cells in the anterior pituitary gland. It is also synthesized and secreted by a wide range of other cells in the body, various immune cells, the brain and the deciduous uterus. Prolactin is synthesized as a pro-hormone.

Prolactin is synthesized and secreted by lactotropic cells in the adenohypophysis (anterior pituitary gland). It is also produced in other tissues including the breast and the deciduous. Pituitary prolactin secretion is regulated by neuroendocrine neurons in the hypothalamus.

Effects (what prolactin is used for)

Prolactin has many effects:

  • Stimulates the mammary glands
  • Desire and sexual gratification
  • Proliferation of oligodendrocyte precursors
  • Production of surfactant in fetal lungs during pregnancy and immune tolerance
  • Prolactin stimulates the mammary glands

The most important effect of prolactin is to stimulate the mammary glands to produce milk. Increased serum prolactin concentrations during pregnancy cause the breast mammary glands to widen and therefore increase milk production. However, elevated levels of progesterone during pregnancy act directly on the breast to stop milk from escaping. It is only when the levels of this hormone decrease after delivery that the milk can come out. Sometimes, newborns secrete a milky substance from their nipples. This happens if the child is affected by prolactin circulating in your body shortly before delivery, and usually disappears immediately after birth.

Sexual gratification. Another effect is to give sexual gratification after intercourse. The hormone represses the effect of dopamine, which is responsible for excitation, causing the refractory period in humans. The amount of prolactin can be an indicator of the level of sexual satisfaction and relaxation. If you have high amounts of prolactin, there is a risk that you will become impotent and decrease sexual desire until it disappears.

Proliferation of oligodendrocyte precursors. Prolactin stimulates the proliferation of oligodendrocyte precursors. These cells, the precursors, differentiate into oligodendrocytes, the cells that form the myelin sheath. Myelin covers the axons of the central nervous system.

Other possible functions of prolactin are:

  • Production of surfactant in the fetal lungs at the end of pregnancy and immune tolerance of the child by the body during the prenatal phase.
  • Production of surfactant in fetal lungs during pregnancy and immune tolerance

Prolactin levels

Prolactin levels vary:

  • During pregnancy, high concentrations of estrogen promote the production of prolactin. High levels further mature the mammary glands, preparing them for breastfeeding.
  • After giving birth, prolactin levels decrease because there is no internal stimulus given by the presence of the child.
  • Breastfeeding promotes greater prolactin release.

High levels of prolactin tend to suppress the ovulatory cycle. With low prolactin values ​​in women, if there are no ovulatory or menstrual problems, there is no problem in conceiving, but breast milk production is not promoted (the main role of prolactin in women). Low prolactin can also occur if dopaminergic drugs are taken, but in any case it is always advisable to consult with a competent doctor who can evaluate the general clinical picture.

In general, in both men and women (non-pregnant) the prolactin values ​​are low, in fact, even in men prolactin is present in small quantities, if it were otherwise, problems regarding testosterone levels and sexual desire would occur.

You can control prolactin levels as part of a sex hormone check up.

High prolactin levels

Hyperprolactinemia is a common condition that can result from a number of causes. A low level has no clinical relevance and cannot be considered hyperprolactinemia.

Conditions that cause the increase in prolactin:

  • Prolactinoma
  • Thyrotropin excess, usually in primary hypothyroidism
  • Side effect of many anti-psychotic drugs
  • Disorders that decrease the level of prolactin
  • Bulimia
  • Excess dopamine.

Prolactin and infertility

How does prolactin affect one’s ability to conceive and keep pregnancy? Prolactin is not limited to increasing milk production – it also affects ovulation and menstrual cycles. This is because breastfeeding women rarely get pregnant. Prolactin inhibits two hormones necessary for ovulation: follicle-stimulating hormone and gonadotropin releasing hormone. When you have high levels of prolactin in your blood, ovulation does not take place and this means that you are not fertile. Menstrual cycles can be irregular.

High prolactin levels in men

Men also have elevated levels of prolactin. Generally, you can see:

  • Azoospermia
  • Decrease in libido e
  • Erectile dysfunction.

Although it is not very common, just go to the doctor to get the correct diagnosis and treatment.

Treatment and care of high prolactin levels

If you have a high level of prolactin, rest assured: the treatment is very effective. Don’t ignore the increases in this hormone, as there may be a basic problem. For example, if hypothyroidism is the cause, then you must treat this disorder. If the excessive amount of prolactin is induced by drugs, stopping taking them will resolve the problem. For high levels of prolactin, medical therapy is the best solution. There are two very effective drugs for this purpose (you can read the report on the effectiveness of the two drugs compared here):

  • Bromocriptine (Parlodel)
  • Cabergoline (Dostinex).

The drugs determine a rapid reduction of prolactin values ​​and consequent remission of clinical symptoms in 95% of cases. They also lead to a reduction in the volume of macroadenomas in 60-70% of cases and to the complete disappearance of the lesion in 10-15% of cases of microadenoma. The wide choice of these dopaminergic drugs allows to overcome intolerance phenomena that can occur with one drug replacing it with another.

Carbegoline and bromocriptine inhibit the synthesis and release of prolactin by acting both at the hypothalamic and pituitary level. Furthermore they are able to reduce the size of the prolactin-secreting pituitary adenomas. Carbegoline has a very long duration of action, so a single dose a week is sufficient. Bromocriptine, on the other hand, must be administered several times during the same day. The side effects of carbegoline are also considerably lower than those of bromocriptine. When present, they manifest themselves from the first administration and consist of a drop in blood pressure, especially during standing, nausea and vomiting, neuropsychiatric disorders, sometimes hallucinations. To minimize the possibility of getting these effects, you need to start treatment with Dostinex in reduced doses: half a 0.5 milligram tablet every week for two weeks until you reach the dosage of 1-2 milligrams per week.

Treatment suspension is usually followed by resumption of tumor growth, so therapy must be continued indefinitely.