Evidence for the presence of endogenous 19-norandrosterone in human urine

In 1997, in the scope of antidoping control in sport, a not inconsiderable number of urine analysed by official laboratories revealed the presence of 19-nortestosterone (19-NT: 17 beta-hydroxyestr-4-en-3-one) metabolites: 19- norandrosterone (19-NA: 3 alpha-hydroxy-5 alpha-estran-17-one) and 19-noret iocholanolone (19-NE: 3 alpha-hydroxy-5 beta-estran-17-one). These repeated results on a short period of time generated some investigations and especi ally the verification of the possible production of these metabolites by an unknown endogenous route in adult entire male. Some experiences were led o n different persons known to be non-treated with steroids and more precisel y with nandrolone. Extractive methods were developed focusing on their sele ctivity, i.e. searching to eliminate at best matrix interferences from the target analytes. Gas chromatography coupled to mass spectrometry (quadrupol e and magnetic instruments) was used to detect, identify and quantify the s uspected signals. Two types of derivatization (TMS and TBDMS), a semi-prepa rative HPLC as well as co-chromatography proved unambiguously the presence, in more than 50% of the analysed urine (n = 40), of 19-NA at concentration s between 0.05 and 0.60 ng/ml. 19-NE was not detected with the developed me thods (LOD<0.02 ng/ml). Experiments led on athletes showed that after a pro longed intense effort, the 19-NA concentration can be increased by a factor varying between 2 and 4. Even if some complementary researches have to be done in order to determine the maximal physiological level of 19-NA and 19- NE, these results should considerably change the strategy of antidoping lab oratories. (C) 1999 Elsevier Science B.V. All rights reserved.