Orally administered micronized progesterone for hormone replacement therapy in women reaches a peak plasma concentration within 4 h and returns to baseline by 6 h Nahoul et al. The residue level found in Canadian beef heifers treated with MGA at a rate of 0.
Zeranol and its metabolites, zearalenone and taleranol, were negative in several in vitro and in vivo genotoxicity assays Bartholomew and Ryan, ; Ingerowski, et al. The main function of progesterone is to regulate the female reproductive cycle for the preparation and maintenance of pregnancy in association with estrogens JECFA,b.
He founded the Centre in Zeranol is a non-steroidal anabolic agent administered subcutaneously as an ear implant in cattle and shows estrogenic activity Katzenellenbogen et al. On the general and procedural issues, the Appellate Body upheld most of the findings and conclusions of the panel, except with respect to the burden of proof in proceedings under the SPS Agreement.
In addition, progesterone did not induce any adverse effects on fertility and development in rats and rhesus monkeys Wharton and Scott, In humans, progestogens are mainly used for contraception and for hormone replacement therapy. Print Steroid Hormone Implants Used for Growth in Food-Producing Animals Since the s, the Food and Drug Administration FDA has approved a number of steroid hormone drugs for use in beef cattle and sheep, including natural estrogen, progesterone, testosterone, and their synthetic versions.