Prolactin (PRL), also known as luteotropic hormone or luteotropin, is a protein that in humans is best known for its role in enabling female mammals to produce milk. Prolactin levels may be checked as part of a sex hormone workup, as elevated prolactin secretion can suppress the secretion of FSH and GnRH, leading to hypogonadism, and sometimes causing erectile dysfunction in men. Prolactin levels may be of some use in distinguishing epileptic seizures from psychogenic non-epileptic seizures. The serum prolactin level usually rises following an epileptic seizure. The test is done to assess the evaluation of Pituitary tumors, Amenorrhea, Galactorrhea, Infertility & Hypogonadism. It also helps in monitoring therapy in prolactin producing tumors.