Application of stable carbon isotope analysis to the detection of testosterone administration to cattle.
The use of anabolic substances is prohibited in food-producing animals throughout the European Union. No method is available to reliably detect the misuse of natural hormones in cattle. A method was developed to detect the abuse of testosterone in cattle fattening. Synthesized testosterone is rather depleted in the (13)C/(12)C ratio. Hence, the method is based on gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis of urine. To select testosterone metabolites and endogenous reference compounds (ERC), the concentration of urinary steroids of cattle was investigated. Dehydroepiandrosterone and androst-5ene-3beta,17alpha-diol were chosen as ERCs to show endogenous (13)C/(12)C ratios. Etiocholanolone and 5alpha-androstane-3beta,17alpha-diol were chosen as the most important testosterone metabolites. Other metabolites known from literature like epitestosterone were less promising. In principle, GC/C/IRMS is a nonspecific method because finally carbon dioxide is analyzed. Therefore, a dedicated cleanup procedure for the selected steroids was developed. By means of proposed confidence intervals in the isotopic composition of ERCs and metabolites, the administration of testosterone to cattle could be detected reliably. Differences of up to 11 per thousand on the delta-scale between ERC and testosterone metabolites were found after testosterone administration, whereas endogenous differences did not exceed 2 per thousand.
Hebestreit
Moritz
M
Institute of Biochemistry, German Sport University Cologne, Carl-Diem-Weg 6, 50933 Cologne, Germany. m.hebestreit@biochem.dshs-koeln.de
Flenker
Ulrich
U
Buisson
Corinne
C
Andre
Francois
F
Le Bizec
Bruno
B
Fry
Hildburg
H
Lang
Melanie
M
Weigert
Angelika Preiss
AP
Heinrich
Katharina
K
Hird
Simon
S
Schänzer
Wilhelm
W
D000818:Animals; D002247:Carbon Isotopes; D002417:Cattle / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D007881:Legislation, Food; D008297:Male; D013739:Testosterone / Q000008:administration & dosage* / Q000652:urine*
D002247:Carbon Isotopes; D013739:Testosterone