Expression of human chorionic gonadotropin (hCG)/luteinizing hormone receptors and regulation of the cyclooxygenase-1 gene by exogenous hCG in human fetal membranes.
The present study characterized hCG/LH receptors from messenger ribonucleic acid (mRNA) to protein and whether exogenous hCG can bind and regulate the expression of the cyclooxygenase-1 (COX-1) gene in human fetal membranes from term pregnancy. Northern blotting showed that fetal membranes contain 6.0, 4.4, 2.4, and 1.4 kilobases of hCG/LH receptor mRNA transcripts. In situ hybridization revealed that amnion, chorion, and decidua contain receptor transcripts. Western immunoblotting and immunocytochemistry showed that amnion, chorion, and decidua also contain an 80-kDa receptor protein. Ligand blotting demonstrated that the 80-kDa receptor protein in fetal membranes can bind [125I]hCG, and this binding was inhibited by excess unlabeled hCG. Treatment of fetal membranes with highly purified hCG resulted in a dose- and time-dependent increase in immunoreactive COX-1 protein. The response of hCG was seen in all layers of fetal membranes. The treatment with hCG also resulted in an increase in steady state COX-1 mRNA levels. The action of hCG was prevented by cotreatment with H-89, an inhibitor of protein kinase A, but not by calphostin or lavendustin, which inhibit protein kinase C and tyrosine kinase, respectively. In summary, human fetal membranes contain hCG receptor transcripts and receptor protein that can bind hCG and up-regulate the expression of COX-1 gene.
Toth
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Department of Obstetrics and Gynecology, University of Louisville School of Medicine, Kentucky 40292, USA.
Li
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Lei
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ZM
Rao
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D000818:Animals; D006063:Chorionic Gonadotropin / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005321:Extraembryonic Membranes / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006706:Homeostasis; D006801:Humans; D011247:Pregnancy; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D011974:Receptors, LH / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013552:Swine; D013997:Time Factors
D006063:Chorionic Gonadotropin; D012333:RNA, Messenger; D011974:Receptors, LH; D011451:Prostaglandin-Endoperoxide Synthases