Variation of the steroid profile in relation to training in women and its importance for anti-doping testing

The urinary steroid module of the Athlete Biological Passport (ABP), monitoring biomarkers over time is limited in female athletes. A serum steroid module has been implemented, including testosterone (T), androstenedione (A4) and the T/A4 ratio, being more stable regarding hormonal fluctuations in women. Acute training may increase serum T and decrease the urinary excretion of androgens. Moreover, the urinary levels of ABP metabolites have been shown to be lower in female athletes compared to sedentary controls. One hypothesis is elimination of some of the androgens via sweat. Therefore, it is of interest to study the urinary and circulatory steroids in relation to training and sweat production.

30 healthy female athletes and 26 untrained BMI-matched controls were included. The athlete's urine and fluid intake was collected over 48 h during a rest- and a training day, and the controls for 24 sedentary hours. Estimated sweat loss was calculated. For the athletes, dried blood spots (DBS) were collected at rest, before and after training and the day after training. Urine was analyzed for the urinary steroid profile by gas chromatography-tandem mass spectrometry and DBS for T and A4 by liquid chromatography-tandem mass spectrometry.

Sweat production was elevated in athletes during the training day versus the rest day, but there were no differences compared to the controls. No significant intra-individual variation (CV %) in urinary steroid profiles was observed; however, controls excreted higher absolute levels of urinary A and 5αAdiol. In DBS, T remained stable whereas a minor increase in A4 was noted in samples taken the day after training. For the T/A4 ratio changes were observed in samples taken after exercise only.

T and A4 in DBS were not affected by acute training. As DBS sample time differed during the day the minor changes in A4 and the T/A4 ratio may be due to diurnal variation and not training dependent effects. In urine certain urinary steroids were lower in the female athletes compared to controls. These results may be of interest when interpreting results of the ABP.