Prospective, randomized, controlled trial.
University-based medical center.
Thirty-seven healthy men aged 18-50 years.
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.
Intratesticular and serum hormone and gonadotropin concentrations.
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, antim¨¹llerian hormone, and 17¦Á-hydroxyprogesterone did not correlate with IT-T. Serum INSL3 increased with the dose of hCG administered and returned to baseline after treatment.
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.
NCT#?00839319.