Prolactin and Osmoregulation

Abstract

The actions of prolactin in hydromineral metabolism in all vertebrate classes are reviewed, and the impact of the studies on nonmammalian vertebrates in providing impetus for comparable research in mammals is emphasized. The teleost bladder is a model system for analyzing the interaction of prolactin and cortisol in transport processes; a parallelism is suggested between this model and the prolactin/cortisol regulation of ion and water movements during milk secretion. The immediate osmoregulatory effects claimed for prolacti in vitro are questioned; however, under organ-culture conditions the action of the hormone is readily demonstrable. Progress in the isolation of teleost prolactin and the role of osmotic factors in regulating prolactin secretion are briefly described.