title: Human LH and hCG stimulate differently the early signalling pathways but result in equal testosterone synthesis in mouse Leydig cells in vitro.
abstract: BACKGROUND
  Human luteinizing hormone (LH) and chorionic gonadotropin (hCG) are glycoprotein hormones regulating development and reproductive functions by acting on the same receptor (LHCGR). We compared the LH and hCG activity in gonadal cells from male mouse in vitro, i.e. primary Leydig cells, which is a common tool used for gonadotropin bioassay. Murine Leydig cells are naturally expressing the murine LH receptor (mLhr), which binds human LH/hCG.
  
  
  METHODS
  Cultured Leydig cells were treated by increasing doses of recombinant LH and hCG, and cell signaling, gene expression and steroid synthesis were evaluated.
  
  
  RESULTS
  We found that hCG is about 10-fold more potent than LH in cAMP recruitment, and slightly but significantly more potent on cAMP-dependent Erk1/2 phosphorylation. However, no significant differences occur between LH and hCG treatments, measured as activation of downstream signals, such as Creb phosphorylation, Stard1 gene expression and testosterone synthesis.
  
  
  CONCLUSIONS
  These data demonstrate that the responses to human LH/hCG are only quantitatively and not qualitatively different in murine cells, at least in terms of cAMP and Erk1/2 activation, and equal in activating downstream steroidogenic events. This is at odds with what we previously described in human primary granulosa cells, where LHCGR mediates a different pattern of signaling cascades, depending on the natural ligand. This finding is relevant for gonadotropin quantification used in the official pharmacopoeia, which are based on murine, in vivo bioassay and rely on the evaluation of long-term, testosterone-dependent effects mediated by rodent receptor.
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Riccetti
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Pascali
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy.
authors.forename: Lisa
authors.initials: L
authors.lastname: Gilioli
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy.|Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy.|Department of Neurosciences, University of Parma, via Voltuno 39/E, 43125, Parma, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Potì
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy.|Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy.
authors.forename: Lavinia Beatrice
authors.initials: LB
authors.lastname: Giva
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy.|Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Marino
authors.affiliation: Department of Laboratory Medicine and Pathological Anatomy, Azienda USL. NOCSAE, Via P. Giardini 1355, 41126, Modena, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Tagliavini
authors.affiliation: Department of Laboratory Medicine and Pathological Anatomy, Azienda USL. NOCSAE, Via P. Giardini 1355, 41126, Modena, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Trenti
authors.affiliation: Endocrinology Unit, Department of Medical and Surgical Sciences, Centre for Applied Biomedical Research (C.R.B.A.), S. Orsola-Malpighi Hospital. Alma Mater University of Bologna, via G. Massarenti 9, I-40138, Bologna, Italy.
authors.forename: Flaminia
authors.initials: F
authors.lastname: Fanelli
authors.affiliation: Endocrinology Unit, Department of Medical and Surgical Sciences, Centre for Applied Biomedical Research (C.R.B.A.), S. Orsola-Malpighi Hospital. Alma Mater University of Bologna, via G. Massarenti 9, I-40138, Bologna, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Mezzullo
authors.affiliation: Endocrinology Unit, Department of Medical and Surgical Sciences, Centre for Applied Biomedical Research (C.R.B.A.), S. Orsola-Malpighi Hospital. Alma Mater University of Bologna, via G. Massarenti 9, I-40138, Bologna, Italy.
authors.forename: Uberto
authors.initials: U
authors.lastname: Pagotto
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy.|Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy.|Department of Medicine, Endocrinology, Metabolism and Geriatrics, Azienda USL. NOCSAE, Via P. Giardini 1355, 41126, Modena, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Simoni
authors.affiliation: Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126, Modena, Italy. livio.casarini@unimore.it.|Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy. livio.casarini@unimore.it.
authors.forename: Livio
authors.initials: L
authors.lastname: Casarini
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007985:Leydig Cells / Q000187:drug effects / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013739:Testosterone / Q000096:biosynthesis*
chemical_list: D006063:Chorionic Gonadotropin; D013739:Testosterone; D007986:Luteinizing Hormone
keywords: Bioassay; LH; Leydig; Testosterone; cAMP; hCG