| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Journal of Clinical Endocrinology & Metabolism, Vol 80, 580-585, Copyright © 1995 by Endocrine Society
ARTICLES |
LS Lin, VJ Roberts and SS Yen
Department of Reproductive Medicine, University of California-San Diego, La Jolla 92093-0802.
Placental GnRH is one of the potential paracrine regulators of hCG secretion from the trophoblasts during pregnancy. Maternal serum hCG levels exhibit an exponential rise during the first 6 weeks of pregnancy, peak at 9-10 weeks, decline to a nadir at 20 weeks, and remain at low levels during the rest of pregnancy. However, the placental content of GnRH does not parallel the time course of hCG secretion, and GnRH messenger ribonucleic acid (mRNA) levels in the placenta remain unchanged during pregnancy. These data do not conform with a simple paracrine mechanism of GnRH as a regulator of hCG secretion. We, therefore, examined the potential variation in GnRH receptor gene expression in the placenta, which may account for the GnRH-mediated dynamic pattern of hCG secretion during gestation. First, we established a functional relationship of GnRH and hCG secretion. Using a placental explant culture system, a dose-response effect of hCG secretion was observed in the placental explant at 9 weeks when treated with GnRH ranging from 10(-9)-10(-7) mol/L. The effect of GnRH was completely blocked by a GnRH antagonist (Nal-Glu). The relative responsiveness of hCG secretion to GnRH stimulation at 10(-7) mol/L was further evaluated in placental explants at 6, 9, and 40 weeks gestation. Whereas the 9-week placenta showed a maximal response (> 300%) relative to the 6-week placenta, there was no response in term placenta. Again, the effects of GnRH on hCG secretion were blocked by Nal-Glu, supporting a receptor-mediated event. Localization of mRNA encoding human GnRH receptor in human placenta at 6, 9, 12, 20, and 40 weeks gestation was established by in situ hybridization. The mRNA signals were present in both cytotrophoblast and syncytiotrophoblast cell layers. Signal intensities varied with gestational ages and were abundant at 6 weeks, peaked at 9 weeks, declined at 12 and 20 weeks, and were undetectable at term. The present study demonstrates, for the first time, that GnRH receptor mRNA is expressed in both cytotrophoblasts and syncytiotrophoblasts and exhibits changes paralleling the time course of hCG secretion during pregnancy. These data provide a mechanistic understanding that the paracrine/autocrine regulation of hCG secretion by placental GnRH is mediated through an increase followed by a decline in GnRH receptor gene expression from the first trimester to term placenta.
This article has been cited by other articles:
 |
|
 |
|
  J. Tesarik, A. Hazout, R. Mendoza-Tesarik, N. Mendoza, and C. Mendoza Beneficial effect of luteal-phase GnRH agonist administration on embryo implantation after ICSI in both GnRH agonist- and antagonist-treated ovarian stimulation cycles Hum. Reprod., October 1, 2006; 21(10): 2572 - 2579. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C.-M. Yeung, B.-S. An, C. K. Cheng, B. K.C. Chow, and P. C.K. Leung Expression and transcriptional regulation of the GnRH receptor gene in human neuronal cells Mol. Hum. Reprod., November 1, 2005; 11(11): 837 - 842. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. K. Cheng and P. C. K. Leung Molecular Biology of Gonadotropin-Releasing Hormone (GnRH)-I, GnRH-II, and Their Receptors in Humans Endocr. Rev., April 1, 2005; 26(2): 283 - 306. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B.-S. An, J.-H. Choi, K.-C. Choi, and P. C. K. Leung Differential Role of Progesterone Receptor Isoforms in the Transcriptional Regulation of Human Gonadotropin-Releasing Hormone I (GnRH I) Receptor, GnRH I, and GnRH II J. Clin. Endocrinol. Metab., February 1, 2005; 90(2): 1106 - 1113. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Tesarik, A. Hazout, and C. Mendoza Enhancement of embryo developmental potential by a single administration of GnRH agonist at the time of implantation Hum. Reprod., May 1, 2004; 19(5): 1176 - 1180. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-S. Chou, A. G. Beristain, C. D. MacCalman, and P. C. K. Leung Cellular Localization of Gonadotropin-Releasing Hormone (GnRH) I and GnRH II in First-Trimester Human Placenta and Decidua J. Clin. Endocrinol. Metab., March 1, 2004; 89(3): 1459 - 1466. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Chen, T. L. Thirkill, P. N. Lohstroh, S. R. Bielmeier, M. G. Narotsky, D. S. Best, R. A. Harrison, K. Natarajan, R. A. Pegram, J. W. Overstreet, et al. Bromodichloromethane Inhibits Human Placental Trophoblast Differentiation Toxicol. Sci., March 1, 2004; 78(1): 166 - 174. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. K. Cheng, B. K. C. Chow, and P. C. K. Leung An Activator Protein 1-Like Motif Mediates 17{beta}-Estradiol Repression of Gonadotropin-Releasing Hormone Receptor Promoter via an Estrogen Receptor {alpha}-Dependent Mechanism in Ovarian and Breast Cancer Cells Mol. Endocrinol., December 1, 2003; 17(12): 2613 - 2629. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Chen, G. C. Douglas, T. L. Thirkill, P. N. Lohstroh, S. R. Bielmeier, M. G. Narotsky, D. S. Best, R. A. Harrison, K. Natarajan, R. A. Pegram, et al. Effect of Bromodichloromethane on Chorionic Gonadotrophin Secretion by Human Placental Trophoblast Cultures Toxicol. Sci., November 1, 2003; 76(1): 75 - 82. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T.A. Bramley, K. Campbell, and G.S. Menzies Human placental GnRH-like factors: II. Inhibition of enzymatic degradation of GnRH-II and [D-Trp6]GnRH ethylamide tracers by human term placental cytosol fractions reveals the presence of GnRH-binding protein(s) Mol. Hum. Reprod., May 1, 2003; 9(5): 291 - 300. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-S. Chou, H. Zhu, E. Shalev, C. D. MacCalman, and P. C. K. Leung The Effects of Gonadotropin-Releasing Hormone (GnRH) I and GnRH II on the Urokinase-Type Plasminogen Activator/Plasminogen Activator Inhibitor System in Human Extravillous Cytotrophoblasts in Vitro J. Clin. Endocrinol. Metab., December 1, 2002; 87(12): 5594 - 5603. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. K. Cheng, C. M. Yeung, R. L. C. Hoo, B. K. C. Chow, and P. C. K. Leung Oct-1 Is Involved in the Transcriptional Repression of the Gonadotropin-Releasing Hormone Receptor Gene Endocrinology, December 1, 2002; 143(12): 4693 - 4701. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. K. Cheng, C. M. Yeung, B. K. C. Chow, and P. C. K. Leung Characterization of a New Upstream GnRH Receptor Promoter in Human Ovarian Granulosa-Luteal Cells Mol. Endocrinol., July 1, 2002; 16(7): 1552 - 1564. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Shozu, H. Sumitani, T. Segawa, H.-J. Yang, K. Murakami, and M. Inoue Inhibition of in Situ Expression of Aromatase P450 in Leiomyoma of the Uterus by Leuprorelin Acetate J. Clin. Endocrinol. Metab., November 1, 2001; 86(11): 5405 - 5411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Grundker, P. Volker, and G. Emons Antiproliferative Signaling of Luteinizing Hormone-Releasing Hormone in Human Endometrial and Ovarian Cancer Cells through G Protein {{alpha}}I-Mediated Activation of Phosphotyrosine Phosphatase Endocrinology, June 1, 2001; 142(6): 2369 - 2380. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. M. Siler-Khodr and M. Grayson Action of Chicken II GnRH on the Human Placenta J. Clin. Endocrinol. Metab., February 1, 2001; 86(2): 804 - 810. [Abstract] [Full Text]
|
|
|
|
|
|
S. K. Kang, C.-J. Tai, P. S. Nathwani, K.-C. Choi, and P. C. K. Leung Stimulation of Mitogen-Activated Protein Kinase by Gonadotropin-Releasing Hormone in Human Granulosa-Luteal Cells Endocrinology, February 1, 2001; 142(2): 671 - 679. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Rama and A.J. Rao Embryo implantation and GnRH antagonists: The search for the human placental GnRH receptor Hum. Reprod., February 1, 2001; 16(2): 201 - 205. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Santra, V. S. Rao, Y.G. Shanker, and A.J. Rao Cloning and characterization of bonnet monkey GnRH receptor Mol. Hum. Reprod., May 1, 2000; 6(5): 415 - 421. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T.A. Bramley and G.S. Menzies Human placental gonadotrophin-releasing hormone-like factors: an artefact of human placental peptidases? Mol. Hum. Reprod., February 1, 2000; 6(2): 113 - 126. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T.A. Bramley, H.P. Boyle, and G.S. Menzies Human placental GnRH-like factors: parallel displacement in GnRH immuno- and receptor-binding assays can be caused by degradation of radiolabelled GnRH tracers Mol. Hum. Reprod., December 1, 1999; 5(12): 1095 - 1106. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Limonta, R. M. Moretti, M. M. Marelli, D. Dondi, M. Parenti, and M. Motta The Luteinizing Hormone-Releasing Hormone Receptor in Human Prostate Cancer Cells: Messenger Ribonucleic Acid Expression, Molecular Size, and Signal Transduction Pathway Endocrinology, November 1, 1999; 140(11): 5250 - 5256. [Abstract] [Full Text]
|
|
|
|
|
|
D. Chardonnens, P. Cameo, M.L. Aubert, F.P. Pralong, D. Islami, A. Campana, R.C. Gaillard, and P. Bischof Modulation of human cytotrophoblastic leptin secretion by interleukin-1{alpha} and 17{beta}-oestradiol and its effect on HCG secretion Mol. Hum. Reprod., November 1, 1999; 5(11): 1077 - 1082. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Knofler What factors regulate HCG production in Down's syndrome pregnancies?: Regulation of HCG during normal gestation and in pregnancies affected by Down's syndrome Mol. Hum. Reprod., October 1, 1999; 5(10): 895 - 897. [Full Text] [PDF]
|
|
|
|
|
|
E. M. Casan, F. Raga, and M. L. Polan GnRH mRNA and protein expression in human preimplantation embryos Mol. Hum. Reprod., March 1, 1999; 5(3): 234 - 239. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Raga, E. M. Casañ, Y. Wen, H.-Y. Huang, F. Bonilla-Musoles, and M. L. Polan Independent Regulation of Matrix Metalloproteinase-9, Tissue Inhibitor of Metalloproteinase-1 (TIMP-1), and TIMP-3 in Human Endometrial Stromal Cells by Gonadotropin-Releasing Hormone: Implications in Early Human Implantation J. Clin. Endocrinol. Metab., February 1, 1999; 84(2): 636 - 642. [Abstract] [Full Text]
|
|
|
|
 |
|
 F. Raga, E. M. Casañ, J. S. Kruessel, Y. Wen, H.-Y. Huang, C. Nezhat, and M. L. Polan Quantitative Gonadotropin-Releasing Hormone Gene Expression and Immunohistochemical Localization in Human Endometrium Throughout the Menstrual Cycle Biol Reprod, July 1, 1998; 59(3): 661 - 669. [Abstract] [Full Text]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
