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A critical review of the environmental occurrence and potential effects in aquatic vertebrates of the potent androgen receptor agonist 17β‐trenbolone
Citation:
Ankley, G., K. Coady, M. Gross, H. Holbech, S. Levine, G. Maack, AND M. Williams. A critical review of the environmental occurrence and potential effects in aquatic vertebrates of the potent androgen receptor agonist 17β‐trenbolone. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 37(8):2064-2078, (2018). https://doi.org/10.1002/etc.4163
Impact/Purpose:
Trenbolone (TRB) acetate is widely-used in some parts of the world for its desirable anabolic effects on livestock. Several TRB metabolites, including 17β‐trenbolone (βTRB), have been detected in surface waters associated with animal feedlots. The βTRB isomer also has been shown to be a very potent androgen receptor agonist in studies with different mammalian and non-mammalian vertebrate species. This paper provides a comprehensive review and synthesis of the existing literature concerning exposure to and biological effects of βTRB, with an emphasis on potential risks to aquatic species. Studies at different sites and types of livestock operations have documented the occurrence of βTRB in adjacent surface waters, typically at low ng/L concentrations. There have been a number of studies with βTRB in fish that show short-term exposures to ng/l water concentrations of the chemical can cause changes in endocrine function, as well as adverse apical effects in chronic exposures. Additional research is warranted to address uncertainties as to the degree/breadth of exposures and potential population-level effects of βTRB in sensitive species, to fully assess ecosystem-level risks.
Description:
Trenbolone acetate is widely used in some parts of the world for its desirable anabolic effects on livestock. Several metabolites of the acetate, including 17β‐trenbolone, have been detected at low nanograms per liter concentrations in surface waters associated with animal feedlots. The 17β‐trenbolone isomer can affect androgen receptor signaling pathways in various vertebrate species at comparatively low concentrations/doses. The present article provides a comprehensive review and synthesis of the existing literature concerning exposure to and biological effects of 17β‐trenbolone, with an emphasis on potential risks to aquatic animals. In vitro studies indicate that, although 17β‐trenbolone can activate several nuclear hormone receptors, its highest affinity is for the androgen receptor in all vertebrate taxa examined, including fish. Exposure of fish to nanograms per liter water concentrations of 17β‐trenbolone can cause changes in endocrine function in the short term, and adverse apical effects in longer exposures during development and reproduction. Impacts on endocrine function typically are indicative of inappropriate androgen receptor signaling, such as changes in sex steroid metabolism, impacts on gonadal stage, and masculinization of females. Exposure of fish to 17β‐trenbolone during sexual differentiation in early development can greatly skew sex ratios, whereas adult exposures can adversely impact fertility and fecundity. To fully assess ecosystem‐level risks, additional research is warranted to address uncertainties as to the degree/breadth of environmental exposures and potential population‐level effects of 17β‐trenbolone in sensitive species.
URLs/Downloads:
DOI: A critical review of the environmental occurrence and potential effects in aquatic vertebrates of the potent androgen receptor agonist 17β‐trenbolone