ABSTRACT
The presence of prolactin (PRL) in large amounts in human amniotic fluid was first demonstrated in the early 1970s shortly after the development of a reliable radioimmunoassay for human PRL. This chapter aims to review information about the biological actions of decidual PRL and, because few clear-cut actions have been defined so far, to speculate on areas which might be worthy of further research. Localization of PRL synthesis to the decidual cells was identified using the techniques of immunohistochemistry and direct in vitro biosynthesis. One physiological role which has been postulated for PRL in the uterus is the regulation of sodium and water transport across the amniotic membrane. The dependency of decidual PRL production on the presence of calcium is one of the few regulatory mechanisms which is shared with that of pituitary PRL secretion. Despite the wealth of information on the nature and control of PRL synthesis and release from decidual tissue, physiological role of decidual PRL remains obscure.
