Anti-17 beta-Methylboldenone polyclonal antibody

A quantitative multi-residue LC- and GC-MS-MS based assay was validated for the analysis of endogenous androgens, progestagens and oestrogens in bovine urine. The method is targeted at analytes indicative of the abuse of nandrolone, boldenone, testosterone, progesterone and oestradiol in cattle. Using a single aliquot of urine, androgens and progestagens are extracted for analysis by GC-MS-MS on a Varian 320 instrument using an enol-TBDMS derivative, while oestrogens are removed into a separate fraction using an extraction derivatisation with dansyl chloride and analysed using LC-MS-MS on a Sciex 5000 instrument. Using a standard addition calibration line approach in pooled bovine urine, the method was found to be sensitive, with limits of detection ranging from 10.9 to 160.7 pg mL(-1), and was linear between the endogenous concentrations and those augmented with 3,000 pg mL(-1). The method is now being applied to large numbers of animals from controlled populations in order to establish thresholds for detecting the abuse of these steroids in food production.

The metabolism of testosterone is revisited. Four previously unreported metabolites were detected in urine after hydrolysis with KOH using a liquid chromatography-tandem mass spectrometry method and precursor ion scan mode. The metabolites were characterized by a product ion scan obtained with accurate mass measurements. Androsta-4,6-dien-3,17-dione, androsta-1,4-dien-3,17-dione, 17-hydroxy-androsta-4,6-dien-3-one and 15-androsten-3,17-dione were proposed as feasible structures for these metabolites on the basis of the mass spectrometry data. The proposed structures were confirmed by analysis of synthetic reference compounds. Only 15-androsten-3,17-dione could not be confirmed, owing to the lack of a commercially available standard. That all four compounds are testosterone metabolites was confirmed by the qualitative analysis of several urine samples collected before and after administration of testosterone undecanoate. The metabolite androsta-1,4-dien-3,17-dione has a structure analogous to that of the exogenous anabolic steroid boldenone. Specific transitions for boldenone and its metabolite 17 beta-hydroxy-5 beta-androst-1-en-3-one were also monitored. Both compounds were also detected after KOH treatment, suggesting that this metabolic pathway is involved in the endogenous detection of boldenone previously reported by several authors.