Quantitative Gonadotropin-Releasing Hormone: DISCUSSION(4)
No data are available from human embryos during the peri-attachment period, and future studies should investigate the presence of GnRH and receptor during human embryonic development. Nevertheless, after embryo-endometrial adhesion, as the embryo invades the uterine endometrial stroma, trophoblastic differentiation into cyto- and syncytiotrophoblast layers occurs, and both are known to produce GnRH as well as to express the GnRH receptor in the first-trimester placenta.
Encouraged by the evidence that large doses of GnRH or GnRH-a were able to induce abortion or delay implantation in rats and baboon monkeys, one of the first clinical GnRH-a experiments in humans was to assess a possible postcoital and postimplantation contraceptive effect. The surprising outcomes of those studies was that high doses of super-reactive GnRH-a not only failed to block implantation or induce abortion in humans but rather seemed to enhance implantation. The exact mechanism by which GnRH-a favors pregnancy during the per-iimplantation period has remained unknown until present. buy cipro
The presence of GnRH and receptor with a dynamic pattern in human endometrium both in the epithelium and stroma provides evidence that this hormone may play a substantial role as a molecular autocrine/paracrine regulator in embryo/endometrial interactions during early implantation.