title: Human chorionic gonadotropin stimulation gives evidence of differences in testicular steroidogenesis in Klinefelter syndrome, as assessed by liquid chromatography-tandem mass spectrometry.
abstract: BACKGROUND
  Men with Klinefelter syndrome (KS) show hypergonadotropic hypogonadism, but the pathogenesis of hypotestosteronemia remains unclear. Testicular steroidogenesis in KS men was evaluated over three decades ago after human chorionic gonadotropin (hCG) stimulation, but inconclusive results were obtained. Intriguingly, some recent studies show increased intratesticular testosterone concentrations in men with KS.
  
  
  OBJECTIVE
  To analyze serum steroid profile, as a proxy of testicular steroidogenesis, after hCG stimulation in KS compared with control men.
  
  
  METHODS
  A prospective, longitudinal, case-control, clinical trial.
  
  
  METHODS
  Thirteen KS patients (36±9 years) not receiving testosterone (TS) replacement therapy and 12 eugonadic controls (32±8 years) were enrolled. Serum steroids were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at baseline and for five consecutive days after intramuscular injection of 5000IU hCG.
  
  
  RESULTS
  Progesterone (P), 17-hydroxyprogesterone (17OHP), TS, and estradiol (E2) showed a significant increase (P<0.001) after hCG stimulation in both groups. On the contrary, androstenedione (AS) and dehydroepiandrosterone did not increase after hCG stimulation. The 17OHP/P ratio increased in both groups (P<0.001), the TS/AS ratio (17β-hydroxysteroid dehydrogenase type 3 (17βHSD3) activity) did not increase after hCG in any group, and the E2/TS ratio (aromatase activity) increased significantly in both groups (P=0.009 in KS and P<0.001 in controls). Luteinizing hormone decreased after hCG in both groups (P=0.014 in KS and P<0.001 in controls), whereas follicle-stimulating hormone decreased only in control men (P<0.001).
  
  
  CONCLUSIONS
  This study demonstrates for the first time using LC-MS/MS that Leydig cells of KS men are able to respond to hCG stimulation and that the first steps of steroidogenesis are fully functional. However, the TS production in KS men is impaired, possibly related to reduced hydroxysteroid deydrogenase activity due to an unfavorable intratesticular metabolic state.
authors.affiliation: Unit of EndocrinologyDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Belli
authors.affiliation: Unit of EndocrinologyDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy Department of MedicineEndocrinology, Metabolism and Geriatrics, Azienda USL of Modena, Modena, Italy santi.daniele@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Santi
authors.affiliation: Unit of EndocrinologyDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Leoni
authors.affiliation: Unit of EndocrinologyDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Dall'Olio
authors.affiliation: Unit of EndocrinologyDepartment of Medical and Surgical Sciences, Centre for Applied Biomedical Research, Unit S. Orsola-Malpighi Hospital, Alma Mater University of Bologna, Bologna, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fanelli
authors.affiliation: Unit of EndocrinologyDepartment of Medical and Surgical Sciences, Centre for Applied Biomedical Research, Unit S. Orsola-Malpighi Hospital, Alma Mater University of Bologna, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Mezzullo
authors.affiliation: Unit of EndocrinologyDepartment of Medical and Surgical Sciences, Centre for Applied Biomedical Research, Unit S. Orsola-Malpighi Hospital, Alma Mater University of Bologna, Bologna, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Pelusi
authors.affiliation: Department of Laboratory Medicine and Pathological AnatomyAzienda USL of Modena, Modena, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Roli
authors.affiliation: Department of Laboratory Medicine and Pathological AnatomyAzienda USL of Modena, Modena, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Tagliavini
authors.affiliation: Department of Laboratory Medicine and Pathological AnatomyAzienda USL of Modena, Modena, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Trenti
authors.affiliation: Department of MedicineEndocrinology, Metabolism and Geriatrics, Azienda USL of Modena, Modena, Italy.
authors.forename: A R
authors.initials: AR
authors.lastname: Granata
authors.affiliation: Unit of EndocrinologyDepartment of Medical and Surgical Sciences, Centre for Applied Biomedical Research, Unit S. Orsola-Malpighi Hospital, Alma Mater University of Bologna, Bologna, Italy.
authors.forename: U
authors.initials: U
authors.lastname: Pagotto
authors.affiliation: Unit of EndocrinologyDepartment of Medical and Surgical Sciences, Centre for Applied Biomedical Research, Unit S. Orsola-Malpighi Hospital, Alma Mater University of Bologna, Bologna, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Pasquali
authors.affiliation: Unit of EndocrinologyDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy Department of MedicineEndocrinology, Metabolism and Geriatrics, Azienda USL of Modena, Modena, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Rochira
authors.affiliation: Unit of EndocrinologyDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Carani
authors.affiliation: Unit of EndocrinologyDepartment of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy Department of MedicineEndocrinology, Metabolism and Geriatrics, Azienda USL of Modena, Modena, Italy Center for Genomic ResearchUniversity of Modena and Reggio Emilia, Modena, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Simoni
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000097:blood; D000328:Adult; D006063:Chorionic Gonadotropin / Q000494:pharmacology / Q000627:therapeutic use*; D002853:Chromatography, Liquid; D004958:Estradiol / Q000097:blood; D006801:Humans; D007713:Klinefelter Syndrome / Q000097:blood / Q000188:drug therapy*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D011374:Progesterone / Q000097:blood; D011446:Prospective Studies; D053719:Tandem Mass Spectrometry; D013737:Testis / Q000187:drug effects*; D013739:Testosterone / Q000097:blood*; D016896:Treatment Outcome
chemical_list: D006063:Chorionic Gonadotropin; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D015067:17-Hydroxysteroid Dehydrogenases; C476565:17beta-hydroxysteroid dehydrogenase type 3