The metabolism of anabolic-androgenic steroids in the greyhound

Background: Effective control of the use of anabolic-androgenic steroids (AASs) in animal sports is essential in order to ensure both animal welfare and integrity. In order to better police their use in Australian and New Zealand greyhound racing, thorough metabolic studies have been carried out on a range of registered human and veterinary AASs available in the region. Results: Canine metabolic data are presented for the AASs boldenone, danazol, ethylestrenol, mesterolone, methandriol, nandrolone and norethandrolone. The principal Phase I metabolic processes observed were the reduction of A-ring unsaturations and/or 3-ketones with either 3 alpha,5 beta- or 3 beta,5 alpha-stereochemistry, the oxidation of secondary 17 beta-hydroxyl groups and 16 alpha-hydroxylation. The Phase II beta-glucuronylation of sterol metabolites was extensive. Conclusion: The presented data have enabled the effective analysis of AASs and their metabolites in competition greyhound urine samples.