Factors affecting urinary excretion of testosterone metabolites conjugated with cysteine.

The implementation of the athlete steroidal passport in doping control analysis aims to detect intra-individual changes in the steroid profile related to the abuse of anabolic steroids. In this context, the study of intrinsic variations associated with each marker is of utmost importance. In the present work, the influence of several factors in the excretion of the recently reported testosterone metabolites conjugated with cysteine (Δ1-AED; 1,4-androstadien-3,17-dione, Δ6-AED; 4,6-androstadien-3,17-dione, Δ6-T; 4,6-androstadien-17β-ol-3-one, and Δ15-AD; 15-androsten-3,17-dione) is evaluated for the first time. Degradation experiments at 37 °C proved that, although the cysteinyl moiety is released, the variation for urinary Δ1-AED/Δ6-AED, Δ1-AED/Δ6-T ratios is less than 30%. Moreover, freeze/thaw cycle testing resulted in RSDs values below 15% for all the analytes. Regarding infradian variability, moderate variations (below 40%) were observed. Additionally, notable alterations in the excretion of these compounds have been observed in the earliest stages of pregnancy. UGT2B17 polymorphism, responsible for the low T/E ratio found in some population, does not influence the excretion of cysteinyl compounds whereas the intake of exogenous substances (alcohol or 5α-reductase inhibitors) dramatically affects their excretion. The urinary concentrations of Δ1-AED, Δ6-AED, and Δ15-AD decreased (<50 %) after the ethanol intake, whereas after the administration of dutasteride, an important increase was observed for the concentrations of Δ6-AED, Δ6-T and Δ15-AD. Overall, the presented data describes the stability of the urinary cysteinyl steroids under the influence of many factors, proving their potential as suitable parameters to be included in the steroidal module of the athlete′s biological passport. Copyright © 2015 John Wiley & Sons, Ltd.