Placental hormones: II.  Immunofluorescence studies of the localization of prolactin/placental lactogen- and human chorionic gonadotrophin-receptors in human and rat placenta. 
Human term placentae and rat placentae of gestation day 15 and 17 were examined for the localization of prolactin (PRL)/placental lactogen (PL) and human chorionic gonadotrophin (hCG) receptors by means of an immunofluorescence technique in order to determine possible target cells for PRL/PL and hCG and to obtain indirect evidence for the localization of steroid producing cells.  In the human placenta, PRL/PL- and hCG-receptors were observed in the syncytiotrophoblast of the chorionic villi and in the giant cells of placental septa and cytotrophoblastic islands in the intervillous space.  In the rat placenta, PRL/PL- and hCG-binding was localized mainly to the giant cells and vacuolated glycogen cells of the basal zone.