title: A role for calcium in gonadotrophin-releasing hormone (GnRH) stimulated secretion of chorionic gonadotrophin by first trimester human placental minces in vitro.
abstract: In vitro studies using first-trimester human placental minces have shown that stimulation of human chorionic gonadotrophin (hCG) secretion by gonadotrophin-releasing hormone (GnRH) is dependent upon the presence of extracellular calcium. Addition of GnRH to first-trimester placental minces in vitro was found to stimulate 45Ca2+ uptake into placental minces, and the process was associated with an increase in immunoreactive hCG in the medium. Addition of GnRH to placental minces preloaded with 45Ca2+ stimulated the efflux of 45Ca2+ within one minute. The calmodulin inhibitors chlorpromazine and trifluoperazine inhibited the basal uptake and efflux of 45Ca2+, suggesting the involvement of calmodulin in the mobilization of calcium in the placenta.
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore.
authors.forename: N
authors.initials: N
authors.lastname: Mathialagan
authors.forename: A J
authors.initials: AJ
authors.lastname: Rao
mesh_terms: D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D002746:Chlorpromazine / Q000494:pharmacology; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D003470:Culture Media; D004492:Edetic Acid / Q000494:pharmacology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology*; D006801:Humans; D010920:Placenta / Q000378:metabolism* / Q000502:physiology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D014268:Trifluoperazine / Q000494:pharmacology
chemical_list: D006063:Chorionic Gonadotropin; D003470:Culture Media; D014268:Trifluoperazine; D007987:Gonadotropin-Releasing Hormone; D004492:Edetic Acid; D002118:Calcium; D002746:Chlorpromazine