Development and application of radioimmunological methods to determine an anabolic compound (trenboloneacetate sup(R)) and its major metabolite (trenbolone) in various tissues and in bovine plasma

For quantitation of the anabolic compound trenboloneacetate sup(R)(TBA) and its major metabolite trenbolone (TBOH) a radioimmunoassay (RIA) was established after raising antibodies in rabbits immunized with TBA-3-(o-carboxi-methyl)-oxime-BSA and TBOH-17β-hemisuccinate-BSA. In order to apply this assay for residue determinations in muscle, liver kidney and fat as well as in plasma of treated animals specific extraction procedures were developed. Specifity, sensitivity, accuracy and reproductibility were tested and the developed methods were shown to be highly reliable. Besides free also conjugated TBOH could be determined after enzyme hydrolysis. The lower limit of sensitivity was around 45 pg; at present 100 tissue samples can be analyzed by one person during one week. With the methods described tissue and plasma samples of 41 heifer calves, 10 bull calves and two steers were analyzed for residues of TBA and TBOH. The animals were treated with various dosages of TBA, alone or in combination with oestradiol-17β. In treated animals the highest residue levels were found in liver, with conjugated TBOH being the major residue fraction (76,4%). Second ranking after liver were fat and kidney tissue with similarly high total residue concentrations, however, free TBOH being the major residue fraction (84,1%) in fat, while each, free and conjugated TBOH, accounted for about 50% in kidney. Lowest residue concentrations with free TBOH being the major residue fraction (91,5%) were found in general in muscular tissue. TBA could only be quantitated in fat (14.2% of total residues). (orig.)