galactorrhea
n. abnormal expression of breast milk, which may occur either in women at times other than when nursing or in men. Lactation is stimulated by the pituitary hormone prolactin, and the neurotransmitter dopamine normally acts to inhibit the release of prolactin. Therefore, administration of dopamine-receptor antagonists (e.g., conventional antipsychotics), which inhibit the effects of dopamine, may cause galactorrhea. Pituitary tumors or injury to the pituitary gland, causing excessive secretion of prolactin, may also result in galactorrhea. The dopamine-receptor agonist bromocriptine may be used to treat the condition.