title: Dynamic GnRH and hCG testing: establishment of new diagnostic reference levels.
abstract: OBJECTIVE
  Gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) stimulation tests may be used to evaluate the pituitary and testicular capacity. Our aim was to evaluate changes in follicular-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone after GnRH and hCG stimulation in healthy men and assess the impact of six single nucleotide polymorphisms on the responses.
  
  
  METHODS
  GnRH and hCG stimulation tests were performed on 77 healthy men, 18-40 years (reference group) at a specialized andrology referral center at a university hospital. The potential influence of the tests was illustrated by results from 45 patients suspected of disordered hypothalamic-pituitary-gonadal axis.
  
  
  METHODS
  Baseline, stimulated, relative and absolute changes in serum FSH and LH were determined by ultrasensitive TRIFMA, and testosterone was determined by LC-MS/MS.
  
  
  RESULTS
  For the reference group, LH and FSH increased almost 400% and 40% during GnRH testing, stimulated levels varied from 4.4 to 58.8 U/L and 0.2 to 11.8 U/L and FSH decreased in nine men. Testosterone increased approximately 110% (range: 18.7-67.6 nmol/L) during hCG testing. None of the polymorphisms had any major impact on the test results. Results from GnRH and hCG tests in patients compared with the reference group showed that the stimulated level and absolute increase in LH showed superior identification of patients compared with the relative increase, and the absolute change in testosterone was superior in identifying men with Leydig cell insufficiency, compared with the relative increase.
  
  
  CONCLUSIONS
  We provide novel reference ranges for GnRH and hCG test in healthy men, which allows future diagnostic evaluation of hypothalamic-pituitary-gonadal disorders in men.
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: A Kirstine
authors.initials: AK
authors.lastname: Bang
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: Loa
authors.initials: L
authors.lastname: Nordkap
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Almstrup
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: Lærke
authors.initials: L
authors.lastname: Priskorn
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.|Department of BiostatisticsUniversity of Copenhagen, Copenhagen, Denmark.
authors.forename: Jørgen Holm
authors.initials: JH
authors.lastname: Petersen
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: Ewa
authors.initials: E
authors.lastname: Rajpert-De Meyts
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Andersson
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Juul
authors.affiliation: Department of Growth and ReproductionRigshospitalet, University of Copenhagen, Copenhagen, Denmark.|International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC)Rigshospitalet, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Jørgensen
mesh_terms: D000293:Adolescent; D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D005838:Genotype; D007987:Gonadotropin-Releasing Hormone / Q000097:blood / Q000494:pharmacology*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009919:Orchiectomy; D010900:Pituitary Diseases / Q000097:blood / Q000175:diagnosis; D010901:Pituitary Function Tests / Q000379:methods* / Q000592:standards*; D012015:Reference Standards; D012189:Retrospective Studies; D012661:Semen / Q000737:chemistry; D013739:Testosterone / Q000097:blood / Q000172:deficiency / Q000235:genetics; D055815:Young Adult
chemical_list: D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone