Determination of urinary testosterone and epitestosterone during pubertal development: a cross-sectional study in 141 normal male subjects

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Abstract
Exogenous testosterone administration is classically detected by measuring the ratio of testosterone to epitestosterone in urine. Athletes are considered to be positive for drug abuse if the urinary testosterone to epitestosterone ratio is greater than 6. We aimed at investigating the urinary excretion of testosterone and epitestosterone during pubertal development.We performed a cross-sectional study of 141 normal male subjects between ages 8 and 26 years.We studied 141 subjects: 32 at stage 1 of Tanner, 27 at stage 2, 30 at stage 3, 25 at stage 4 and 27 at stage 5.Subjects performed a 24-hour urine collection. Urinary testosterone and epitestosterone were measured by gas chromatography-mass spectrometry with selected ion monitoring.Urinary testosterone was 20.5 +/- 1.7 nmol/24 h (mean +/- SEM) at stage 1, 49 +/- 2.9 at stage 2, 98.8 +/- 3.4 at stage 3, 371.8 +/- 21.8 at stage 4 and 403.4 +/- 16.1 nmol/24h at stage 5. Urinary epitestosterone was 13.1 +/- 1.5 nmol/24h at stage 1, 29.1 +/- 3.3 at stage 2, 48.3 +/- 3.7 at stage 3, 156.3 +/- 14.8 at stage 4 and 221.1 +/- 18.6 nmol/24h at stage 5. The urinary excretions of both steroids increased significantly during puberty and were highly correlated with chronological age (P < 0.001). Comparison of the correlation slopes (P < 0.001) showed that the urinary profiles of testosterone and epitestosterone are not parallel during pubertal development. Two subjects presented a testosterone to epitestosterone ratio above 6, corresponding to a low urinary concentration of epitestosterone, without pathological explanation.Testosterone and epitestosterone do not present the same urinary profiles throughout puberty. Marked increases of the testosterone to epitestosterone ratio can be observed at this period and may interfere with doping tests.