Schönfelder M, Hofmann H, Schulz T, Engl T, Kemper D, Mayr B, Rautenberg C, Oberhoffer R, Thieme D
Potential detection of low-dose transdermal testosterone administration in blood, urine and saliva
Administration of low amounts of endogenous hormones - so called micro-dosages - are supposed to represent a major challenge in doping analysis. To model such a situation, we have studied transdermal administrations of 2.4 mg/24h testosterone patches and examined various steroid concentrations in blood, urine and saliva of 11 volunteers. Multiple samples were collected at t=0, 3, 6, 9, 24, 48 and 72 h in four different phases, i.e. all combinations with/without physical exercise and with/without testosterone. Testosterone was analyzed by enzyme-linked-immuno-assay as well as by mass spectrometry in validated in an accredited anti-doping laboratory.
Circadian controls with and without exercise did not provoke prominent alterations of whole, free, and salivary testosterone. Testosterone application for 24h led to a significant (all p<0.001) mean increase above controls: total testosterone (median: 5.2 vs. 8.0ng/ml), free testosterone (median: 11.3 vs. 15.6pg/ml), and salivary testosterone (median: 62.4 vs. 99.9pg/ml). Additionally, all three testosterone measurements indicated significant correlations to each other (all r>0.538, all p<.001). Circadian-matching showed peaking testosterone values after 6h and 9h, reaching highest augmentation up to 252.6±123.5% in saliva after 9h. After removal of testosterone patch, all testosterone levels in blood, saliva, and urine returned to baseline within 24h. Different techniques of hormone detection (ELISA, GC-MS/MS, LC-MS/MS) indicated significant correlations.
Results indicate that saliva, blood, and urine exhibit comparable hormone augmentation during micro-dose testosterone application, indicating a possible consideration in future doping analysis. The inter-individual variability was high in all biofluids, requiring the use of individual biological passport rather than statistical values.