Product-to-Parent Reversion of Trenbolone: Unrecognized Risks for Endocrine Disruption

• Published in: Science (American Association for the Advancement of Science) 2013-10, Vol.342 (6156), p.347-351
• Main Authors: Qu, Shen, Kolodziej, Edward P., Long, Sarah A., Gloer, James B., Patterson, Eric V., Baltrusaitis, Jonas, Jones, Gerrad D., Benchetler, Peter V., Cole, Emily A., Kimbrough, Kaitlin C., Tarnoff, Matthew D., Cwiertny, David M.
• Format: Article
• Language: English
• Subjects: Acetates; Anabolic Agents - adverse effects; Anabolic Agents - chemistry; Anabolic Agents - metabolism; Animal productions; Animals; Applied sciences; Aquatic ecosystems; Biological and medical sciences; Cattle; Chemical contaminants; Contaminants; Continental surface waters; Darkness; Dehydration; Desiccation; Earth sciences; Earth, ocean, space; Ecology; Endocrine disruptors; Endocrine Disruptors - adverse effects; Endocrine Disruptors - chemistry; Endocrine Disruptors - metabolism; Endocrinology; Engineering and environment geology. Geothermics; Environmental assessment; Environmental Health; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Humans; Hydrogen-Ion Concentration; Metabolites; Natural water pollution; Photolysis; Pollution; Pollution sources; Pollution, environment geology; Property reversion; Regrowth; Reversion; Risk; Risk Assessment; Steroids; Surface water; Sustainable agriculture; Temperature; Terrestrial animal productions; Transformations; Trenbolone Acetate - adverse effects; Trenbolone Acetate - chemistry; Trenbolone Acetate - metabolism; Vertebrates; Water - chemistry; Water Pollutants - adverse effects; Water Pollutants - chemistry; Water Pollutants - metabolism; Water treatment and pollution
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1243192

Trenbolone acetate (TBA) is a high-value steroidal growth promoter often administered to beef cattle, whose metabolites are potent endocrine-disrupting compounds. We performed laboratory and field phototransformation experiments to assess the fate of TBA metabolites and their photoproducts. Unexpectedly, we observed that the rapid photohydration of TBA metabolites is reversible under conditions representative of those in surface waters (pH 7, 25°C). This product-toparent reversion mechanism results in diurnal cycling and substantial regeneration of TBA metabolites at rates that are strongly temperature-and pH-dependent. Photoproducts can also react to produce structural analogs of TBA metabolites. These reactions also occur in structurally similar steroids, including human Pharmaceuticals, which suggests that predictive fate models and regulatory risk assessment paradigms must account for transformation products of high-risk environmental contaminants such as endocrine-disrupting steroids.