PARENT SESSION
PT2 - Endocrine Disruption
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P546) Contribution of the growth promoter trenbolone to androgenic activity of a feedlot discharge.

Makynen, Elizabeth^*,1, Durhan, Elizabeth¹, Lambright, Christy², Wilson, Vickie², Gray, L², Lazorchak, James³, Smith, Mark⁴, Weichman, Barry⁵, Ankley, Gerald¹, ¹ U.S. EPA Mid-continent Ecology Division, Duluth, Mn, USA² U.S. EPA Reproductive Toxicology Division, Research Triangle Park, NC, USA³ U.S. EPA Molecular Ecology Research Branch, Cincinnati, OH, USA⁴ Sobran Inc. c/o U.S.EPA, Cincinnati, OH, USA⁵ PAI Associates, c/o U.S. EPA, Cincinnati, OH, USA

ABSTRACT- Little is known concerning the potential ecological effects of hormonally-active substances associated with discharges from confined animal feeding operations. Trenbolone acetate is a synthetic anabolic steroid that is widely used in beef production in the US. Metabolites of the acetate include the stereoisomers 17- and 17 -trenbolone, both of which are stable in animal wastes and relatively potent androgens in reproduction assays with the fathead minnow, laboratory rat and other species. The purpose of this study was to evaluate the occurrence of 17- and 17-trenbolone in a beef feedlot discharge, and in river water downstream from the discharge. In addition, we evaluated in vitro androgenic activity of the discharge using CV-1 cells that had been transiently cotransfected with human androgen receptor and MMTV-luciferase reporter gene constructs. Samples were collected on several different occasions during the spring and summer of 2002. Whole water samples from the discharge caused a significant androgenic response in the CV-1 cells, and contained detectable concentrations of 17- and 17-trenbolone as indicated by high-pressure liquid chromatography with fluorescence detection. The samples currently are being subjected to confirmatory mass spectral analyses for the identification of trenbolone. The instrumental measurements then will be assessed relative to the CV-1 data to quantitatively ascertain the contribution of trenbolone to the observed in vitro androgenic activity. This abstract does not reflect EPA policy.

Key words: androgenic activity, fathead minnow, androgen receptor