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Articles |
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UCLA Olympic Analytical Laboratory, Department of Molecular and Medical Pharmacology and
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Department of Medicine, University of California at Los Angeles, Los Angeles, CA 90025.
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The word "elevated" is used to refer to a result that is above the administrative cutoff.
a Address correspondence to this author at: UCLA Olympic Analytical Laboratory, Department of Molecular and Medical Pharmacology, University of California at Los Angeles, 2122 Granville Ave., Los Angeles, CA 90025-6106. Fax 310-206-9077; e-mail
rodrigoa{at}ucla.edu.
Background: Carbon isotope ratio methods are used in doping control to determine whether urinary steroids are endogenous or pharmaceutical.
Methods: Gas chromatography-combustion-isotope ratio mass
spectrometry (GC-C-IRMS) was used to determine the 
13C
values for 5{beta}-androstane-3
,17{beta}-diyl diacetate (5{beta}A),
5-androstane-3,17{beta}-diyl diacetate (5A), and
5{beta}-pregnane-3,20-diyl diacetate (5{beta}P) in a control group of
73 healthy males and 6 athletes with testosterone/epitestosterone
ratios (T/E) >6.
Results: The within-assay precision SDs for 5{beta}A, 5A, and
5{beta}P were ± 0.27
, ± 0.38, and ± 0.28,
respectively. The between-assay precision SDs ranged from ±
0.40 to ± 0.52. The system suitability and batch acceptance
scheme is based on SDs. For the control group, the mean
13C (SD) values were -25.69 (± 0.92),
-26.35 (± 0.68), and -24.26 (± 0.70), for 5{beta}A, 5A,
and 5{beta}P, respectively. 5{beta}P was greater than 5{beta}A and 5A
(P <0.01), and 5{beta}A was greater than 5A
(P <0.01). The means - 3 SD were -28.46,
-28.39, and -26.37 for 5{beta}A, 5A, and 5{beta}P, respectively.
The maximum difference between 5{beta}P and 5{beta}A was 3.2, and
the maximum 5{beta}A/5{beta}P was 1.13. Three athletes with chronically
elevated T/Es had 13C values consistent with
testosterone administration and three did not.
Conclusions: This GC-C-IRMS assay of urine diols has low within-
and between-assay SDs; therefore, analysis of one urine sample suffices
for doping control. The means, SDs, ±3 SDs, and ranges of
13C values in a control group are established. In
comparison, testosterone users have low 5{beta}A and 5A, large
differences between 5{beta}A or 5A and 5{beta}P, and high 5{beta}A/5{beta}P and
5A/5{beta}P ratios.
The following articles in journals at HighWire Press have cited this article:
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  J. J. Schulze, J. Lundmark, M. Garle, I. Skilving, L. Ekstrom, and A. Rane Doping Test Results Dependent on Genotype of Uridine Diphospho-Glucuronosyl Transferase 2B17, the Major Enzyme for Testosterone Glucuronidation J. Clin. Endocrinol. Metab., July 1, 2008; 93(7): 2500 - 2506. [Abstract] [Full Text] [PDF]
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 C Saudan, N Baume, N Robinson, L Avois, P Mangin, and M Saugy Testosterone and doping control Br. J. Sports Med., July 1, 2006; 40(suppl_1): i21 - i24. [Abstract] [Full Text] [PDF]
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 N. Baume, L. Avois, C. Schweizer, C. Cardis, J. Dvorak, M. Cauderay, P. Mangin, and M. Saugy [13C]Nandrolone Excretion in Trained Athletes: Interindividual Variability in Metabolism Clin. Chem., February 1, 2004; 50(2): 355 - 364. [Abstract] [Full Text] [PDF]
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R. Aguilera, C. K. Hatton, and D. H. Catlin Detection of Epitestosterone Doping by Isotope Ratio Mass Spectrometry Clin. Chem., April 1, 2002; 48(4): 629 - 636. [Abstract] [Full Text] [PDF]
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