A pituitary disorder characterized by excessive amounts of the hormone prolactin. It is most commonly caused by a pituitary prolactin-secreting tumor or by certain psychotropic medications, such as conventional antipsychotics (e.g., haloperidol [haldol]). Galactorrhea, amenorrhea (failure to menstruate), and decreased libido in women and gynecomastia (breast enlargement) and decreased sexual drive in men are common manifestations.
Excess levels of prolactin in the blood. In males, this is usually due to a pituitary tumor. Such excess prolactin results in testis atrophy, a reduction in testosterone production, and a high incidence of impotence. Removal of the tumor reverses these characteristics.
An excess secretion of prolactin thought to be due to hypothalamic-pituitary dysfunction. This is usually associated with amenorrhea with or without galactorrhea.