Use of isotope ratio mass spectrometry to detect doping with oral testosterone undecanoate: inter-individual variability of 13C/12C ratio.
The metabolic effect of multiple oral testosterone undecanoate (TU) doses over 4 weeks was assessed in seven voluntary men. The protocol was designed to detect accumulation of the substance by choosing the appropriate spot urines collections time and to study the urinary clearance of the substance after weeks of treatment. Urines were analysed by a new GC/C/isotope ratio mass spectrometry (IRMS) method to establish the delta(13)C-values of testosterone metabolites (androsterone and etiocholanolone) together with an endogenous reference compound (16(5alpha)-androsten-3alpha-ol). The significant differences in inter-individual metabolism following TU intake was illustrated by large variations in delta(13)C-values of both T metabolites (maximum Deltadelta(13)C-values = 5.5 per thousand), as well as by very stable longitudinal T/E profiles and carbon isotopic ratios in the first hours following administration. According to T/E ratios and delta(13)C-values, the washout period after 80 mg TU intake was less than 48 h for all subjects and no accumulation phenomenon was observed upon chronic oral administration.
Baume
Norbert
N
Laboratoire Suisse d'Analyse du Dopage, Institut Universitaire de Médecine Légale, Lausanne, Switzerland.
Saudan
Christophe
C
Desmarchelier
Aurélien
A
Strahm
Emmanuel
E
Sottas
Pierre-Edouard
PE
Bagutti
Carlo
C
Cauderay
Michel
M
Schumacher
Yorck Olaf
YO
Mangin
Patrice
P
Saugy
Martial
M
D000284:Administration, Oral; D000328:Adult; D002247:Carbon Isotopes; D004300:Doping in Sports; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D014644:Genetic Variation; D006801:Humans; D008297:Male; D012016:Reference Values; D015813:Substance Abuse Detection / Q000379:methods*; D013739:Testosterone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism / Q000652:urine; D013997:Time Factors
D002247:Carbon Isotopes; C015529:testosterone glucuronate; D013739:Testosterone; C010792:testosterone undecanoate