What are the dangers of hyperprolactinemia?

Hyperprolactinemia is a hypothalamic-pituitary-gonadal axis dysfunction disease, with a prevalence of 0.4% in the general population, 4.35% in patients with primary amenorrhea, and 9% to 17% in patients with reproductive dysfunction, and the prevalence in women is higher than that in men. The main manifestations in women are amenorrhea, galactorrhea, oligomenorrhea, infertility, etc., which seriously affect people's health and quality of life. So, what are the hazards of hyperprolactinemia? The main hazards are:

1. Irregular menstruation and infertility

HPRL affects the function of the hypothalamus-pituitary-ovarian axis. Increased prolactin in the patient's blood will lead to a decrease in the ovarian response to gonadotropin, thereby inhibiting the development and maturation of follicles, failing to form the estrogen peak and luteinizing hormone peak before ovulation, and directly inhibiting the ovarian synthesis of estradiol and progesterone, leading to ovulation disorders, oligomenorrhea or amenorrhea; decreased libido, atrophy of genitals (such as ovaries and uterus), and even osteoporosis or fracture risk in severe cases; HPRL can also interfere with fertilization and embryonic development, leading to infertility, miscarriage, etc. [3].

2. Milk leakage

The main function of PRL is to promote breast growth and milk secretion. The incidence of galactorrhea in HPRL patients is 70% to 98%. Galactorrhea is overt or appears as watery, serous or milky fluid when the breasts are squeezed. In most cases, the amount of secretion is not large, and in severe cases, it can flow out on its own. Long-term galactorrhea can cause psychological stress and even psychological problems in patients.

3. Secondary endometrial lesions

HPRL inhibits ovulation and leads to a lack of progesterone synthesis in the body due to its inhibitory effect on the reproductive axis. Despite low estrogen levels, long-term anovulation exposes the endometrium to unprotected estrogen stimulation for a long time, increasing the risk of patients developing endometrial lesions such as various types of endometrial hyperplasia, atypical polypoid adenomyomas, and even endometrial adenocarcinoma [4].

4. Tumor compression manifestations

Tumor space-occupying symptoms, manifested as headaches, are mainly caused by the enlargement of the tumor, which compresses the sella turcica and blood vessels. About 2/3 of patients with pituitary adenomas have headaches. Visual dysfunction includes decreased vision, visual field loss, papilledema, optic nerve atrophy, etc.; there are also nausea, vomiting, drowsiness, coma and other symptoms of intracranial compression, epileptic seizures, cerebrospinal fluid rhinorrhea, etc. A small number of patients have acute pituitary apoplexy.

5. Affects sugar metabolism

The effect of HPRL on women depends on the biological effect of PRL. In addition to its inhibitory effect on the reproductive axis, PRL also has a regulatory effect on other hormones. HPRL caused by pituitary adenoma can aggravate insulin resistance, interfere with glucose metabolism, and even increase the incidence of diabetes.

6. Increased risk of cardiovascular disease

PRL has a vasoconstrictive function. Studies have shown that PRL levels during pregnancy may induce gestational hypertension and preeclampsia. HPRL in early menopause can reduce the bioavailability of NO, reduce the substrate of NO synthase in endothelial cells, increase the production of oxygen free radicals, lead to increased arterial blood pressure, increased aortic systolic and diastolic pressure, and increased pulse pressure, thereby aggravating vascular stenosis, causing vascular atherosclerosis, and increasing the incidence of cardiovascular disease [5]. In addition, the low gonadotropin and low estrogen state caused by long-term HPRL can also increase the incidence of cardiovascular disease.

7. Immune System

PRL receptors have been detected on the cell membranes of T lymphocytes, B cells, and macrophages. PRL plays an important regulatory role in human immune response. Moderately elevated levels of PRL stimulate immunity, while high levels of PRL inhibit immunity. For example, during pregnancy, the increase in PRL can significantly alleviate the symptoms of certain autoimmune diseases.

8. Water and sodium retention

PRL can increase the intestinal absorption of water and salt, reduce the activity of renal tubular Na-K-ATPase, and reduce the secretion of Na+ and K+. Therefore, hyperprolactinemia can increase water and sodium retention[6].