Development of mass spectrometry-based methods for the detection of 11-ketotestosterone and 11-ketodihydrotestosterone.

The anabolic properties of 11-hydroxyandrostenedione (OHA4) and its physiologically active metabolites 11-ketotestosterone (KT) and 11-ketodihydrotestosterone (KDHT) have been discussed in several recent publications. Especially KT has become readily available via internet-based providers. No doping control methods for the detection of KT or KDHT exist, neither on the initial testing procedure level nor as confirmatory assay. Probing for the misuse of adrenosterone, the prohormone of OHA4, has already been addressed, and the suggested marker for its misuse was mainly the urinary concentration of 11-hydroxyandrosterone (OHA). In addition, for confirmation purposes, the carbon isotope ratios (CIR) were taken into consideration. The urinary concentration of OHA is highly variable, and the endogenous dilution after exogenous administration may therefore be considerable; hence, described approaches resulted in short detection times. In this study, the human metabolism of KT was investigated in order to provide additional means for the detection of KT and its prohormone OHA4. Two volunteers (one female and one male) orally administered 20 mg of KT each, and urine samples were collected for 5 days. Urinary concentrations of KT and its metabolites were investigated, and a reference population encompassing 220 male and female athletes was investigated in order to elucidate preliminary thresholds. As confirmation procedure, an isotope ratio mass spectrometry-based method was developed in order to determine the CIR of KT and relevant metabolites. The developed methods enabled the detection of exogenous KT for more than 20 h after a single oral administration, which is comparable to a single oral testosterone administration.