Recent progress in the detection of the administration of natural hormones: Special focus on Testosterone

A pilot study on subject-based comprehensive steroid profiling: novel biomarkers to detect testosterone misuse in sports

CONTEXT

Until now, the testosterone/epitestosterone (T/E) ratio is the main marker for the detection of testosterone (T) misuse in athletes. As this marker can be influenced by a number of confounding factors, additional steroid profile parameters indicating T misuse can provide substantiating evidence of doping with endogenous steroids. The evaluation of a steroid profile is currently based upon population statistics. As large inter-individual variations exist, a paradigm shift towards subject-based references is ongoing in doping analysis.

OBJECTIVE

Proposition of new biomarkers for the detection of testosterone in sports using extensive steroid profiling and an adaptive model based upon Bayesian inference.

SUBJECTS

Six healthy male volunteers were administered with testosterone undecanoate. Population statistics were performed upon steroid profiles from 2014 male Caucasian athletes participating in official sport competition.

DESIGN

An extended search for new biomarkers in a comprehensive steroid profile combined with Bayesian inference techniques as used in the athlete biological passport resulted in a selection of additional biomarkers that may improve detection of testosterone misuse in sports.

RESULTS

Apart from T/E, 4 other steroid ratios (6α-OH-androstenedione/16α-OH-dehydroepiandrostenedione, 4-OH-androstenedione/16α-OH-androstenedione, 7α-OH-testosterone/7β-OH-dehydro-epiandrostenedione and dihydrotestosterone/5β-androstane-3α,17β-diol) were identified as sensitive urinary biomarkers for T misuse. These new biomarkers were rated according to relative response, parameter stability, detection time and discriminative power.

CONCLUSION

Newly selected biomarkers were found suitable for individual referencing within the concept of the Athlete's Biological Passport. The parameters showed improved detection time and discriminative power compared to the T/E ratio. Such biomarkers can support the evidence of doping with small oral doses of testosterone.

Searching for new markers of endogenous steroid administration in athletes: “looking outside the metabolic box”

A simple means of detecting the abuse of steroids that also occur naturally is a problem facing doping control laboratories. Specific markers are required to allow the detection of the administration of these steroids. These markers are commonly measured using a set of data obtained from the screening of samples by gas chromatography-mass spectrometry (GC-MS). Doping control laboratories further need to confirm identified abuse using techniques such as gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). An interesting urinary species was found while following the pharmacokinetics and changes to the steroid profile from single and multiple oral doses of the International Olympic Committee/World Anti Doping Agency (IOC/WADA) prohibited substance, dehydroepiandrosterone (DHEA). The urine samples collected from the administration studies were subject to GC-MS and GC-C-IRMS steroid analysis following cleanup by solid phase extraction techniques. A useful urinary product of DHEA administration was detected in the urine samples from each of the administration studies and was identified by GC-MS experiments to be 3alpha,5-cyclo-5alpha-androstan-6beta-ol-17-one (3alpha,5-cyclo). This compound occurs naturally but the concentrations of 3alpha,5-cyclo were elevated following both the single DHEA administration (up to 385 ng/mL) and multiple DHEA administrations (up to 1240 ng/mL), in relation to those observed prior to these administrations (70 and 80 ng/mL, respectively). A reference distribution of urine samples collected from elite athletes (n = 632) enabled the natural concentration range of 3alpha,5-cyclo to be established (0-280 ng/mL), with a mean concentration of 22 ng/mL. Based on this an upper 3alpha,5-cyclo concentration limit of 140 ng/mL is proposed as a GC-MS screening marker of DHEA abuse in athletes. GC-C-IRMS analysis revealed significant 13C depletion of 3alpha,5-cyclo following DHEA administration. In the single administration study, the delta13C value of 3alpha,5-cyclo changed from -24.3 per thousand to a minimum value of -31.1 per thousand at 9 h post-administration, before returning to its original value after 48 h. The multiple administration study had a minimum delta13C 3alpha,5-cyclo of -33.9 per thousand during the administration phase in contrast to the initial value of -24.2 per thousand. Preliminary studies have shown 3alpha,5-cyclo to most likely be produced from DHEA sulfate found at high levels in urine. The complementary use of GC-MS and GC-C-IRMS to identify new markers of steroid abuse and the application of screening criteria incorporating such markers could also be adapted by doping control laboratories to detect metabolites of androstenedione, testosterone and dihydrotestosterone abuse.