Detection and quantitation of 19-norandrosterone in urine by isotope dilution-mass spectrometry.
A highly accurate method has been developed for detection and quantitation of 19-norandrosterone, the major urinary metabolite of 19-nortestosterone in man. A suitable 14C labelled standard was obtained by i.m. injection of [4-14C]-19-nortestosterone into a human volunteer. A fixed amount of this internal standard was added to a fixed amount of urine and the mixture was treated with Helix pomatia for 24 h. After extraction and purification by t.l.c., the mixture was converted into methoxime-trimethylsilyl derivative and analyzed by combined GC-MS. Unlabelled 19-norandrosterone could be quantitated from the ratio between the tracings of the ions at m/z 256 and m/z 258, corresponding to M-90-31 ions. In alternative procedures the ions at m/z 346 and 348 (corresponding to the M-31 ions) could be used. Under the conditions employed, urinary 19-norandrosterone could be identified and quantitated in concentrations exceeding 20 ng/ml. The steroid could be traced in urine up to 6 weeks after i.m. administration of 25 mg of the decanoate of 19-nortestosterone (Deca-Durabol). When using radioimmunoassay with antibodies towards unmetabolized 19-nortestosterone, it was possible to trace urinary 19-nortestosterone only for 1-2 weeks after the administration. The present method has been successfully used for analysis of 19-norandrosterone in urine samples obtained from athletes involved in competition.
D004962:Estranes / Q000652:urine*; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D009277:Nandrolone / Q000378:metabolism
D004962:Estranes; C036015:19-norandrosterone; D009277:Nandrolone