Detection of calcitonin and parathyroid hormone in the human placenta at term. In this investigation we proved immunoreactive calcitonin and immunoreactive parathyroid hormone in the maternal side of the human placenta. We used the immunocytochemical staining technique (Peroxidase-Antiperoxidase-method) by Sternberger where different antibodies react. We could see calcitonin and parathyroid hormone mainly in the decidual cells as well as in the cytotrophoblastic cells of the maternal part of the placenta.