Human Placental Lactogen in Choriocarcinoma of the Male. Measurement by Radioimmunoassay

Abstract

The Human placenta contains a substance which cross-reacts immunologically to a limited extent with human growth hormone, to which Josimovich and MacLaren gave the name human placental lactogen (HPL) (1). Breast stimulation (1), luteotrophic activity (2) and synergism with human growth hormone in the rat tibia assay (3) have been described for this substance, prepared from extracts of human placentas. Strong evidence of trophoblastic origin is indicated by its high concentration in placental extracts, its presence in trophoblastic but not decidual tissue, its appearance in maternal serum and urine during pregnancy, and disappearance following delivery, its persistence following hypophysectomy in one pregnant patient, and its absence in maternal and fetal pituitaries (3).