Vol. 182, No. 2, 1992 January 31, 1992 BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Pages 481-486 EVIDENCE FOR THE EXPRESSION OF GROWTH HORMONE RECEPTORS IN HUMAN PLACENTA Francis FRANKENNE*, Eliane ALSAT**, Marie-Louise SCIPPO*, Ahmed IGOUT*, Georges HENNEN* and Daniele EVAIN-BRION** *Human Biochemistry, University of Liege, B23,4OOO Liege, Belgium **Laboratoire de Physiopathologie du Developpement, CNRS URA 1337. Ecole Normale Superieure, 75230 Paris CEDEX 05, France Received November 14, 1991 ABSTRACT : Since human placenta produces a growth hormone variant, it seemed important to search for evidence of GH receptors in that organ. Evidence for the expression of the GH receptor (GHR) gene was obtained by northern blot analysis. In addition, GHR poly A+ RNA was detected in RNA from cultured trophoblastic cells, but not from placenta fibroblasts. There was a low but significant specific binding of pituitary GH-N and placental GH-V to placenta plasma membranes. Both variants apparently bound to the same receptor, which is present in the first trimester as well as in the term placenta. These results suggest that placental GH may have paracrine or autocrine functions in the placenta 0 1992 Academic Press, Inc. Human placenta has been shown to produce its own growth hormone variant (1,2). That variant is specified by the hGH-V gene (3,4) in the syncytiotrophoblast (5). The GH-V protein is likely to share some activities of pituitary GH-N since it displays a higher potency for binding to rabbit liver GH receptors (1). Placental GH-V replaces pituitary GH-N in maternal serum after mid-pregnancy, but has not been detected in the fetal circulation (1). The hGH-N gene is intensively expressed in the pituitary, but not in normal placenta (2). Nevertheless, trophoblastic cells in culture are able to produce the GH-N protein in some circumstances (6). Some uneventful pregnancy cases associated with a deletion of the hGH-V gene in the feto-placental genome have been reported (7). Recently, we have obtained evidence that the hGH-N gene is expressed in such a placenta (to be published). Beside a potential endocrine role that placental GI-Is could exert in the maternal organism, 0006-291X/92 $1.50 481 Copyright 0 1992 by Academic Press, Inc. All rights of reproduction in any form reserved.