HUMAN INTERMEDIATE TROPHOBLASTS EXPRESS CHORIONIC GONADOTROPIN LUTEINIZING HORMONE-RECEPTOR GENE/

Human cyto- and syncytiotrophoblasts have recently been shown to conta in functional hCG/LH receptors. The present study investigated whether human intermediate trophoblasts also contain these receptors. Six imp lantation sites from 4-8 wk of pregnancy were processed for in situ hy bridization for hCG/LH receptors coupled with immunocytochemistry for human placental lactogen (hPL), an endocrine marker for intermediate t rophoblasts. In addition, the sections were also double-immunostained for hCG/LH receptor and hPL proteins. The results showed that some but not all the intermediate trophoblasts contained hCG/LH receptors. The intermediate trophoblasts in endovascular locations contained more re ceptors than those in perivascular locations. Villus syncytiotrophobla sts contained the highest level of receptors, followed by intermediate trophoblasts in endovascular and perivascular locations and then vill us cytotrophoblasts. These data, demonstrating the presence of hCG/LH receptors in intermediate trophoblasts, suggest a possible role for hC G in trophoblast invasion and maternal recognition of pregnancy.