The Role of Trophoblast Differentiation in the Control of the hCG and hPL Genes
One of the unique features of the human placenta is its continued differentiation during gestation. Progeny of mitotically active mononucleated cytotrophoblasts fuse to form the mitotically inactive syncytiotrophoblast (1–3). During the differentiation, two major peptide hormones are produced, human chorionic gonadotropin (hCG) and human placental lactogen (hPL). Their temporal appearance in maternal serum during pregnancy is different: hCG peaks in the first trimester, while hPL reaches maximal levels at term. Therefore, the factors controlling their expression are not identical (4–7).
KeywordsHuman Placenta Hydatidiform Mole Cytotrophoblastic Cell Placental Villus Normal Placenta
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