Luteotrophic, Immunologic and Electrophoretic Properties of Human Placental Lactogen

Abstract

A previously described potent lactogenic fraction of the human placenta was shown to be closely related, immunologically, to human pituitary growth hormone. The potent luteotrophic effects of human placental lactogen (HPL), as well as those of sheep prolactin and human pituitary growth hormone, are demonstrated by the maintenance of induced decidual reactions after hypophysectomy in pseudopregnant rats. Further evidence of the immunologic and biologic specificity of the cross-reaction of HPL with an antiserum to human pituitary growth hormone, including its immunologic differentiation from human chorionic gonadotrophin, is provided by comparisons in a series of studies utilizing electrophoretic, immunologic and biologic inhibition assays. These studies thus provide biologic and immunologic means of testing for the presence of HPL in the tissues and sera of human pregnancy.