Trenbolone growth promotant: covalent DNA binding in rat liver and in Salmonella typhimurium, and mutagenicity in the Ames test

Hormone Use in Food Animal Production: Assessing Potential Dietary Exposures and Breast Cancer Risk

In recent years, increasing attention has been paid to the role of hormones in breast cancer etiology, following reports that heightened levels of endogenous hormones and exposure to exogenous hormones and other endocrine-disrupting chemicals through food and the environment are associated with increased breast cancer risk. Seven hormone drugs (testosterone propionate, trenbolone acetate, estradiol, zeranol, progesterone, melengestrol acetate, and bovine somatotropin) are approved by the U.S. Food and Drug Administration for use in food animals. There is concern that these drugs or their biologically active metabolites may accumulate in edible tissues, potentially increasing the risk of exposure for consumers. To date, the potential for human exposure to residues of these compounds in animal products, as well as the risks that may result from this exposure, is poorly understood. In this paper, we discuss the existing scientific evidence examining the toxicological significance of exposure to hormones used in food animal production in relation to breast cancer risk. Through a discussion of U.S. federal regulatory programs and the primary literature, we interpret the state of surveillance for residues of hormone drugs in animal products and discuss trends in meat consumption in relation to the potential for hormone exposure. Given the lack of chronic bioassays of oral toxicity of the seven hormone compounds in the public literature and the limitations of existing residue surveillance programs, it is not currently possible to provide a quantitative characterization of risks that result from the use of hormonal drugs in food animal production, complicating our understanding of the role of dietary hormone exposure in the population burden of breast cancer.

Risk assessment of growth hormones and antimicrobial residues in meat

Growth promoters including hormonal substances and antibiotics are used legally and illegally in food producing animals for the growth promotion of livestock animals. Hormonal substances still under debate in terms of their human health impacts are estradiol-17β, progesterone, testosterone, zeranol, trenbolone, and melengestrol acetate (MGA) . Many of the risk assessment results of natural steroid hormones have presented negligible impacts when they are used under good veterinary practices. For synthetic hormonelike substances, ADIs and MRLs have been established for food safety along with the approval of animal treatment. Small amounts of antibiotics added to feedstuff present growth promotion effects via the prevention of infectious diseases at doses lower than therapeutic dose. The induction of antimicrobial resistant bacteria and the disruption of normal human intestinal flora are major concerns in terms of human health impact. Regulatory guidance such as ADIs and MRLs fully reflect the impact on human gastrointestinal microflora. However, before deciding on any risk management options, risk assessments of antimicrobial resistance require large-scale evidence regarding the relationship between antimicrobial use in food-producing animals and the occurrence of antimicrobial resistance in human pathogens. In this article, the risk profiles of hormonal and antibacterial growth promoters are provided based on recent toxicity and human exposure information, and recommendations for risk management to prevent human health impacts by the use of growth promoters are also presented.

Induction of micronuclei in V79 cells by the anabolic doping steroids tetrahydrogestrinone and trenbolone

The synthetic steroid tetrahydrogestrinone is a new "designer drug" and was recently detected to be illegally used in sports. It is chemically closely related to trenbolone that is known as an animal growth promoter. The potencies of trenbolone, tetrahydrogestrinone and testosterone to induce micronuclei in V79 cells in vitro were determined. CREST analysis was employed to differentiate between aneugenic or clastogenic mechanisms. Cytotoxicity and an influence on the cell cycle were assessed in parallel. Incubations with testosterone, at concentrations between 3 and 300 microM, failed to induce micronuclei. By contrast, tetrahydrogestrinone and trenbolone increased the rate of micronuclei significantly, up to a doubling of the micronuclei rate of untreated controls. Tetrahydrogestrinone and trenbolone displayed a bell-shaped dose-response curve, with maximal effects observed at 3 and 30 microM, respectively. The micronuclei induced by tetrahydrogestrinone and trenbolone were predominantly kinetochor (CREST) positive, pointing to an aneugenic mode of action. This may be related to the specific structure of both molecules with a system of activated double bonds. As the genotoxic effect of tetrahydrogestrinone at a chromosomal level appears at a low concentration range, it cannot be ruled out that tetrahydrogestrinone presents a genotoxic hazard on a chromosomal level under conditions of its current misuse in sports.

Structural and functional diversity of microbial communities from a lake sediment contaminated with trenbolone, an endocrine-disrupting chemical

Effects of trenbolone (TBOH), a hormone used in cattle production, on the structure and function of microbial communities in a fresh water sediment from a lake in Southern Germany were studied in a microcosm experiment. The microbial community structure and the total gene pool of the sediment, assessed by 16S rRNA/rDNA and RAPD fingerprint analysis, respectively, were not significantly affected by TBOH. In contrast, the N-acetyl-glucosaminidase activity was almost 50% lower in TBOH treated samples (P<0.05). Also, the substrate utilization potential, measured using the BIOLOG system, was reduced after TBOH treatment. Interestingly, this potential did not recover at the end of the experiment, i.e. 19 days after the addition of the chemical. Repeated application of TBOH did not lead to an additional reduction in the substrate utilization potential. Overall results indicate that microbial community function was more sensitive to TBOH treatment than the community structure and the total gene pool.