Human Prolactin

Abstract
IN 1954, Forbes et al.1 described a syndrome of abnormal lactation and amenorrhea in 15 patients, many of whom had pituitary tumors. Although the authors suggested that the tumors were producing excessive quantities of prolactin, only recently has enough evidence accumulated to substantiate the existence of the human hormone. In lower vertebrate forms, on the other hand, it has long been realized that pituitary prolactin is an important hormone with diverse functions in reproductive physiology.2 In the euryhaline fish, which migrate from salt to fresh water during reproduction, prolactin inhibits sodium efflux, preventing a dilutional hyponatremic state. Hypophysectomized fish cannot . . .