Urinary Concentrations of Steroids in Bulls under Anabolic Treatment by Revalor-XS® Implant.

Despite the European ban of using anabolics in food-producing animals, growth promoters might still be illegally used in the European Union. To control the food chain and guarantee consumers' health, there is a need of highly sensitive analytical methods for the identification of marker residues of such treatments. In the present study, a group of bulls (n = 16) received trenbolone acetate (200mg) and estradiol (40mg) by a commercial ear implant during a time range of 71 days, and a second group (n = 16) was kept for control. The aim of the research was to measure the residual urinary concentrations of the administered drugs (beta-trenbolone and beta-estradiol), their main metabolites (alpha-trenbolone and alpha-estradiol), and possible alterations of the urinary profile of other endogenous hormones metabolically related. The analytical method was based on liquid chromatography-tandem mass spectrometry. Results showed average urinary concentrations of alpha-trenbolone and alpha-estradiol during treatment in the range of (0.81 divided by 2.1) ng mL(-1) and (0.96 divided by 4.4) ng mL(-1), respectively, whereas beta-trenbolone and beta-estradiol exhibit urinary concentrations lower than 0.22 ng mL(-1) in both cases. Data obtained from the urinary profiles of endogenous steroids indicate that they could be useful to indirectly detect the ongoing treatment.