Prolactin is a polypeptide composed of 199 amino acids that is secreted primarily by the lactotrope cells, which are located in the anterior pituitary gland. To a lesser extent, it can be produced in other organs or areas, such as the immune system, the central nervous system, the placenta, the uterus or the mammary glands.
The purpose of prolactin is the production of breast milk during both pregnancy and lactation. The secretion is pulsatile, and these pulses increase after meals and during sleep.
Excluding the time of pregnancy and lactation, prolactin levels are usually quite normal. However, its secretion is regulated by various metabolic, hormonal or neurotransmitter mechanisms. If there is some kind of imbalance in these mechanisms, variations in prolactin levels can occur.
What causes the increase in prolactin?
It should be mentioned that not all high prolactin levels are due to disease or pathology, but there are some alterations due to pregnancy, lactation, pathological or physical stress, after eating or after intense physical activity.
If the increase in prolactin has a pathological cause, most of them are secondary to some type of pharmacological treatment, such as antidepressants, antipsychotics, drugs of abuse, antihypertensives, opiates… It can also originate from a pituitary adenoma that produces prolactin.
Some diseases can also elevate prolactin levels, such as liver failure, renal failure, polycystic ovary syndrome, primary hypothyroidism or almost any alteration in the regulatory area of the hypothalamus and pituitary gland, as well as involvement or injury to the spinal cord or rib cage.
To assess high prolactin levels, some variables must be taken into account, such as macropolactin, which is usually asymptomatic and untreated. It should also be noted that the prolactin level is usually higher in women than in men as a result of estrogen stimulation, so prolactin levels may be higher during ovulation or during the luteal phase of the menstrual cycle, so it is advisable to measure it during the follicular phase.
What are the symptoms of high prolactin levels?
The main signs caused by elevated prolactin levels is a reduction of sex hormones, so that libido decreases, menstruation becomes irregular or absent, fertility decreases, erections are reduced in men….
In turn, if the excess of prolactin is associated with a pituitary adenoma, symptoms such as visual disturbances, headache… These symptoms can be associated with those of the diseases that cause high levels of prolactin, or the side effects of the drugs that increase it.
Thus, there are numerous causes for which an increase in the level of prolactin in the blood can occur, so it is necessary to consult an endocrinologist to make a differential diagnosis and to propose a possible treatment, which, in most cases, is usually of a conservative type.