Pilot Study of Serum Inhibin B as a Potential Marker of Testosterone Doping in Weight Lifting Men

OBJECTIVE: The aim of this study was to explore effectors of the pituitary-testicular axis suitable as potential biochemical markers to screen for testosterone doping. DESIGN: Pilot study with male bodybuilding athletes with a self-reported history of testosterone doping (repeated intramuscular administration of testosterone preparations, last injection 8 weeks or less ago) compared with an equal sized control group matched for sex, age, and body mass index. SETTING: Endocrine outpatients. PARTICIPANTS: Fifteen healthy young men of white background. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Inhibin B, testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH). RESULTS: Although the levels of testosterone, LH, and FSH did not differ between the 2 groups, the serum concentrations of inhibin B in individuals with a history of testosterone doping were exclusively at or below the lower limit of the normal range for adult men (100-400 pg/mL). Inhibin B was significantly lower in those men who used testosterone for weight lifting (76.1 +/- 36.3 ng/L [mean +/- SD]) than in controls (182.1 +/- 35.4 ng/L). CONCLUSION: A low concentration of serum inhibin B may reflect the application of exogenous testosterone and appears to be a potential marker associated with anabolic androgenic steroid doping.