What is PRL?
Prolactin is a hormone produced by the Pituitary gland which is situated at the base of the brain. Prolactin is normally produced in both males and non-pregnant females in small amounts. The main function of this hormone is to stimulate milk production (lactation) after childbirth, so, it is also known as the milk-producing hormone. The levels of prolactin hormone are generally high during pregnancy and after childbirth. But, high levels of prolactin can also be seen in many disease conditions in both men and women. The prolactin test measures the levels of prolactin in the blood, to check and monitor the associated disease condition.
Why is PRL done?
To investigate the cause of abnormal breast milk discharge (galactorrhea), menstrual irregularities or infertility in non-pregnant women
To evaluate the role of prolactin in case of lactation failure in women after childbirth
To investigate the cause of erection problems, testicular failure or abnormal breast discharge in men
To investigate the cause of loss of sex drive (libido) in both men and women
To detect and monitor the progress of prolactinoma (tumor of the pituitary gland that causes high levels of prolactin) in both men and women
What does PRL Measure?
The prolactin (PRL) test measures the levels of prolactin in blood. The prolactin hormone is produced by the pituitary gland which is located at the base of the brain. The primary function of this hormone is to help in lactation i.e. production of milk after childbirth. Prolactin levels are usually high during pregnancy and after childbirth. During pregnancy, this hormone along with other hormones like estrogen and progesterone stimulates the breasts for milk production. After the childbirth, it helps to maintain the breast milk production. Suckling of the breasts by the baby is important for the release of prolactin hormone. If a woman stops breastfeeding, the level of prolactin hormone will return to normal.
Abnormally high levels of prolactin are seen in certain disease conditions like prolactinoma (non-cancerous tumor of the pituitary gland) in men and women. It is generally benign (non-cancerous) in nature and is seen more commonly in women. If the tumor is quite large, it can put pressure on the optic nerve and the patient may present with headache and visual disturbances.
Interpreting PRL results
High levels of prolactin can be seen in:
Tumors of the pituitary gland that produces and releases prolactin (Prolactinoma)
Diseases of the hypothalamus (a gland located in the brain)
Polycystic ovary disease (PCOD)
Conditions like anorexia nervosa (eating disorder)
Low levels of prolactin can be seen in:
Patients taking bromocriptine
Pituitary deficiency like necrosis or infarction of the pituitary gland