IGF-II is important in early placentation, growth, and development of the fetal-placental unit and in transport across fetal membranes in humans. However, its synthesis does not seem to be correlated only with the mitogenic activity of cells, but also with invasive trophoblastic processes in the first trimester of gestation. Some have found mRNAs for IGF-II in the syncytiotrophoblast, but others have not ; IGF-II peptide was found in full-term syncytiotrophoblast, but cells containing its mRNA are not always identical with the cells that contain the protein, because immunoreactive cells may have taken up IGF-II secreted by neighboring cells. buy ortho tri-cyclen online
Little is known about the distribution of IGF receptors in the human placenta. IGF-I receptors have been found in several regions of the human term placenta, including along the basal membrane of the villous syncytiotrophoblast, but none was found on the luminal side of that villous syncytiotrophoblast. This disagrees with our results suggesting that IGF-II is taken up from the maternal blood.