Hyperprolactinemia is a relatively common disorder that occurs when there is an excess of the hormone prolactin in the body. It can affect men and women. In women, it can cause, among other things, amenorrhea, where menstruation either stops for no reason, or never starts in the first place. It can cause impotence in men.
There are many possible causes of hyperprolactinemia. Prolactin is primarily produced by the pituitary gland. It is constantly being released unless dopamine, released by the hypothalamus, tells the pituitary to stop. Dopamine travels a complex network of tiny veins to send the signal to the pituitary gland; any interference along dopamine’s route can mean that the prolactin keeps being produced. If the hypothalamus receives signals that there is too much prolactin in the body, it responds by producing more dopamine. The overabundance of dopamine then can block production of the hormone GnRH, which can cause further problems.
The most common causes of hyperprolactinemia, however, are prolactin secreting pituitary tumors (prolactinomas). Approximately five to ten percent of the adult population may have these tumors, and often they do not know it. Because men often have less obvious symptoms than women, the tumors may not be detected in men until they are large.
Certain common medications can also cause hyperprolactinemia.