Ovine placental lactogen in the cotyledonary and intercotyledonary placenta of the ewe.

Antibodies raised against purified ovine placental lactogen were used to demonstrate the cellular localization of the hormone in tissues of the ewe placenta and chorionic membranes by immunofluorescence and immunoperoxidase techniques. Although binucleate cells have been shown to appear as early as Day 16 of pregnancy, ovine placental lactogen was not detected in the trophoblast until Day 22, and in substnatial numbers of cells until Day 80, of gestation. In the more mature placenta, lactogen-immunoreactive material was demonstrated in (a) binucleate cells of the fetal trophoblast, (b) uninucleate cells associated with the maternal epithelium syncytium and (c) binucleate cells of the chorionic membranes.