Evidence for the expression of growth hormone receptors in human placenta

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.