Product-to-parent reversion of trenbolone: unrecognized risks for endocrine disruption.
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-to-parent 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.
Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA 52242-1527, USA.
Shen
S
Qu
Edward P
EP
Kolodziej
Sarah A
SA
Long
James B
JB
Gloer
Eric V
EV
Patterson
Jonas
J
Baltrusaitis
Gerrad D
GD
Jones
Peter V
PV
Benchetler
Emily A
EA
Cole
Kaitlin C
KC
Kimbrough
Matthew D
MD
Tarnoff
David M
DM
Cwiertny
D045930:Anabolic Agents / Q000009:adverse effects / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002417:Cattle; D003624:Darkness; D003890:Desiccation; D052244:Endocrine Disruptors / Q000009:adverse effects / Q000737:chemistry* / Q000378:metabolism*; D004782:Environmental Health; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010782:Photolysis; D018570:Risk Assessment; D013696:Temperature; D014204:Trenbolone Acetate / Q000009:adverse effects / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000737:chemistry*; D014873:Water Pollutants / Q000009:adverse effects / Q000737:chemistry* / Q000378:metabolism
D045930:Anabolic Agents; D052244:Endocrine Disruptors; D014873:Water Pollutants; D014867:Water; D014204:Trenbolone Acetate