title: Serum insulin-like factor 3 is highly correlated with intratesticular testosterone in normal men with acute, experimental gonadotropin deficiency stimulated with low-dose human chorionic gonadotropin: a randomized, controlled trial.
abstract: OBJECTIVE
  To study the potential role for using serum biomarkers, including insulin-like factor 3 (INSL3), 17α-hydroxyprogesterone, antimüllerian hormone, and inhibin B, as correlates of intratesticular T (IT-T) concentrations in men.
  
  
  METHODS
  Prospective, randomized, controlled trial.
  
  
  METHODS
  University-based medical center.
  
  
  METHODS
  Thirty-seven healthy men aged 18-50 years.
  
  
  METHODS
  All men received the GnRH antagonist acyline, plus very low doses of hCG (0 IU, 15 IU, 60 IU, or 125 IU) SC every other day or 7.5 g T gel daily (75 mg delivered). The IT-T concentrations obtained by percutaneous testicular aspiration with simultaneous serum protein and steroid concentrations were measured at baseline and after 10 days of treatment.
  
  
  METHODS
  Intratesticular and serum hormone and gonadotropin concentrations.
  
  
  RESULTS
  After 10 days of gonadotropin suppression, serum INSL3 decreased by more than 90% and correlated highly with IT-T concentrations. In contrast, serum inhibin B, antimüllerian hormone, and 17α-hydroxyprogesterone did not correlate with IT-T. Serum INSL3 increased with the dose of hCG administered and returned to baseline after treatment.
  
  
  CONCLUSIONS
  Serum INSL3 correlates highly with IT-T and serum T concentrations during acute gonadotropin suppression in men. Human chorionic gonadotropin stimulates dose-dependent increases in INSL3 and IT-T in healthy men and might be a useful biomarker of IT-T concentration in some clinical settings.
  
  
  BACKGROUND
  NCT# 00839319.
authors.affiliation: Center for Research in Reproduction and Contraception, Department of Medicine, University of Washington, Seattle, Washington. Electronic address: mylang@u.washington.edu.
authors.forename: Mara Y
authors.initials: MY
authors.lastname: Roth
authors.affiliation: Department of Obstetrics and Gynecology, University of Washington, Seattle, Washington.
authors.forename: Kat
authors.initials: K
authors.lastname: Lin
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Katrine
authors.initials: K
authors.lastname: Bay
authors.affiliation: Center for Research in Reproduction and Contraception, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: John K
authors.initials: JK
authors.lastname: Amory
authors.affiliation: Center for Research in Reproduction and Contraception, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Anawalt
authors.affiliation: Center for Research in Reproduction and Contraception, Department of Medicine, University of Washington, Seattle, Washington; Geriatric Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington.
authors.forename: Alvin M
authors.initials: AM
authors.lastname: Matsumoto
authors.affiliation: Geriatric Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington.
authors.forename: Brett T
authors.initials: BT
authors.lastname: Marck
authors.affiliation: Center for Research in Reproduction and Contraception, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: William J
authors.initials: WJ
authors.lastname: Bremner
authors.affiliation: Center for Research in Reproduction and Contraception, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: Page
mesh_terms: D019326:17-alpha-Hydroxyprogesterone / Q000097:blood; D000293:Adolescent; D000328:Adult; D054304:Anti-Mullerian Hormone / Q000097:blood; D015415:Biomarkers / Q000097:blood; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors; D006062:Gonadotropins / Q000172:deficiency*; D006801:Humans; D007265:Inhibins / Q000097:blood; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000494:pharmacology; D011506:Proteins; D013737:Testis / Q000187:drug effects* / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D006063:Chorionic Gonadotropin; D006062:Gonadotropins; D007328:Insulin; C084797:Leydig insulin-like protein; D009842:Oligopeptides; D011506:Proteins; C422364:inhibin B; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007265:Inhibins; D019326:17-alpha-Hydroxyprogesterone; D054304:Anti-Mullerian Hormone; C109238:acyline