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Prolactin: Function and Hyperprolactinemia
Prolactin is a proteohormone formed in the adenohypophysis in the anterior pituitary gland. In women, prolactin is responsible for mammary gland growth during pregnancy and for milk secretion (lactation). The physiological significance of prolactin in men is unclear, elevated levels can be found among others in stress and after sex. Prolactin inhibits in men the secretion of GnRH, LH and FSH and testosterone. Further function: triggering the brood care behavior. This is also true to a small extent for men, elevated prolactin levels can be demonstrated peri- and postpartum.
Standard value for men:
3,0–15 ng/ml. Pronounced circadian rhythm with nocturnal peak concentrations, the measurement is recommended in the morning at least 3~h after getting up.
Laboratory test method:
Indications for men:
Perform a lab test for prolactin for men with hypogonadism, gynecomastia, galactorrhoea, decreased libido and erectile dysfunction.
Differential Diagnosis of Hyperprolactinemia
The causes of low-grade hyperprolactinemia below 100 ng/ml are complex: stress, alcohol, sex, medications (psychotropic drugs, verapamil, metoclopramide, opiates, H2 blocker), hypothyroidism and numerous systemic diseases such as renal insufficiency, hypothyroidism, cirrhosis or epilepsy. Repeated tests are recommended.
Persistently elevated levels above 100 ng/ml suggest a pituitary adenoma. The level of prolactin production correlates with tumor size (<250 ng/ml microadenoma below 10 mm, >250 ng/ml macroadenoma greater than 10 mm).
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Deutsche Version: Prolaktin und Differentialdiagnose der Hyperprolaktinämie