Identification of some important metabolites of boldenone in urine and feces of cattle by gas chromatography mass spectrometry

17 alpha-Boldenone (17 alpha-BOL) and/or 17 beta-boldenone (17 beta-BOL) ap pear occasionally in fecal matter of cattle. In addition to 17 alpha-BOL, a whole array of boldenone related substances can be found in the same sampl es. In vitro experiments with microsomal liver preparations and isolated he patocytes combined with the excretion profiles found in urine and feces sam ples of in vivo experiments made it possible to identify several metabolite s of 17 beta-BOL in 17 beta-BOL positive feces samples. In one animal treat ed with 17 beta-BOL, no 17 beta-BOL or its metabolites were present before treatment and most of these compounds disappeared,gradually in time after t he treatment was stopped. It is not clear what the origin is of 17 alpha-BO L and boldenone metabolites in samples screened routinely for the abuse of anabolic steroids and considered to be 'negative' because of the absence of 17 beta-BOL since other workers showed some evidence that 17 alpha-BOL can be of endogenous origin. However, in our hands, most of these 17 alpha-BOL positive samples, obtained during routinely performed screenings of cattle , contained large amounts of Delta(4)-androstene-3,17-dione (PLED), which n ormally is absent from routinely screened negative samples. Furthermore, AE D was absent in all samples obtained from the animals treated with 17 beta- BOL. We have no direct evidence that 17 alpha-BOL or 17 beta-BOL is of endo genous origin.