Profiles of steroid hormones in beef from steers implanted with Synovex-S (estradiol benzoate and progesterone) in comparison to control steers

Profiles of steroid hormones (androgens, estrogens, progestogens and cortic oids), their precursors and metabolites were analyzed in nine beef samples obtained from steers which had received the anabolic implant Synovex-S (200 mg progesterone plus 20 mg estradiol benzoate) and in nine samples from co ntrol steers. Analysis of phenolic steroids was performed by enzyme immunoa ssay after separation by HPLC. Neutral steroids were determined by CC-MS. C oncentrations of the hormones progesterone and 17 beta-estradiol, of their precursors and metabolites (pregnenolone, 17 alpha-hydroxyprogesterone, deh ydroepiandrosterone, androstenedione, epitestosterone, alpha-androsterone, 17 alpha-estradiol, and estrone) and of the corticosteroids cortisone and h ydrocortisone did not differ significantly between treatments (P>0.05) but the ratio of 17 beta-estradiol to its metabolites and the cortisone/hydroco rtisone ratio were significantly higher in beef from treated steers (P<0.01 ). Concentrations of testosterone and 5 alpha-dihydrotestosterone were belo w the determination limits (10 ng/kg and 20 ng/kg, respectively) in both tr eated and control steers.