title: Expression of luteinizing hormone/human chorionic gonadotrophin (LH/HCG) receptor mRNA in the human ovary.
abstract: The gonadotrophins follicle stimulating hormone (FSH) and luteinizing hormone (LH) are key hormones in the regulation of ovarian function. In the present study, the expression of LH/human chorionic gonadotrophin (HCG) receptor mRNAs in the human ovary was examined. Northern blot analysis was used to measure relative amounts of LH/HCG receptor mRNA, and in-situ hybridization was used to localize LH/HCG receptor transcripts. Northern blot analysis of human ovaries detected three transcripts (5.4, 3.6 and 2.4 kb) for the LH/HCG receptor. LH/HCG receptor mRNA concentrations increased from preovulatory follicles to the corpus luteum of the midluteal phase, and decreased at the late luteal phase. Using in-situ hybridization, LH/HCG receptor mRNA was located predominantly in granulosa cells in the same follicle. Cloning of the human LH/HCG receptor cDNA previously revealed the existence of two alternative forms of the receptor differing by the presence (HLH-Ra) and absence (HLH-Rb) of 62 amino acids by exon 9. We have studied the functional significance of these receptor isoforms and have confirmed that they are generated by alternative splicing. A reverse transcription-polymerase chain reaction amplification was used to detect different isoforms of LH receptor mRNAs in ovary and placenta. The expression of the two mRNA forms of LH/HCG receptor were detected in ovary, and at very low concentrations in placenta. Treatment with HCG caused a dose-dependent increase in cAMP production with an initial response evident at approximately 1 ng/ml HCG in COS-7 cells expressing HLH-Ra. However, a complete loss of signal transduction was found in cells transfected with the truncated HLH-Rb.
authors.affiliation: Department of Obstetrics and Gynecology, Gunma University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Minegishi
authors.forename: M
authors.initials: M
authors.lastname: Tano
authors.forename: Y
authors.initials: Y
authors.lastname: Abe
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Ibuki
authors.forename: K
authors.initials: K
authors.lastname: Miyamoto
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D019556:COS Cells; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D017403:In Situ Hybridization; D008183:Luteal Phase / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D011974:Receptors, LH / Q000235:genetics*; D014162:Transfection
chemical_list: D006063:Chorionic Gonadotropin; D017931:DNA Primers; D012333:RNA, Messenger; D011974:Receptors, LH; D000242:Cyclic AMP