Prolactin

See also: hyperprolactinemia - prolactin and pregnancy

What is Prolactin

Prolactin (PRL) is a hormone secreted by the anterior pituitary gland that has the breast as the target organ. It is therefore a typically female hormone that participates together with estrogen in the development of the breast during puberty.

Functions

Prolactin, as its name suggests, is a very important lactation hormone. Less than normal secretion during breastfeeding significantly reduces milk production by the mammary glands.

The effects of this hormone on the male organism have not yet been completely defined. A prolactin hypersecretion in humans correlates to lack of sexual desire, gynecomastia and impotence. In fact, a function of prolactin is to inhibit testosterone and mobilize fatty acids.

In females an excessive production of this hormone is accompanied by galactorrhea (secretion of milk in the absence of pregnancy) and suspension of the menstrual cycle. This condition, if external to pregnancy, is often caused by a small pituitary adenoma (neoplasm).

Prolactin and Stress

In sports, the analysis of prolactin in the blood is often crossed with that of the so-called "stress hormones" such as cortisol and ACTH (corticotropin). It has been seen that the secretion of this hormone increases considerably after exhausting physical exercise. It is therefore assumed that high concentrations of prolactin are related to what is called super training, or a physical condition in which, due to excessive training and competitive commitments, the body does not respond adequately to training stimuli and tends to lower its own. performance level.

In the female athlete an excess of prolactin is, together with other hormones, at the base of what is called the female athlete's triad, a rather serious condition, which is associated with overtraining, characterized by osteoporosis, amenorrhea and eating disorders generally.

Even during particularly stressful events such as fasting, acute myocardial infarction, burns and prolonged psycho-physical stress, prolactin secretion increases significantly. In these conditions the organism makes a desperate attempt to survive, increasing support for primary vital functions (heart, brain, kidneys etc.) and at the same time turning off all the "accessory" functions. Sexual desire and muscle mass under such conditions are completely superfluous and this is why prolactin goes on to switch off, together with other hormones, first the production of testosterone and then of all the other gonadotropins (FSH and LH). Here are explained the effects of hypersecretion of prolactin that we have before (impotence in man, alteration of menstrual flow in women and mobilization of fats to ensure energy supply to vital organs).