Identification of Metabolites of Trenbolone Acetate in Androgenic Runoff from a Beef Feedlot

摘要

Little is known concerning the potential ecological effects of hormonally active substances associated with discharges from animal feeding operations.Trenbolone acetate is a synthetic anabolic steroid that is widely used in the United States to promote growth of beef cattle.Metabolites of trenbolone acetate include the stereoisomers 17 alpha- and 17 beta-trenbolone,both of which are stable in animal wastes and are relatively potent androgens in fish and mammals.Our purpose in this study was to evaluate the occurrence of 17 alpha- and 17 beta-trenbolone in a beef cattle feedlot discharge and in river water upstream and downstream from the discharge.In conjunction with that effort,we measured in vitro androgenic activity of the discharge using CV-1 cells that had been transiently cotrans-fected with human androgen receptor and reporter gene constructs.Samples were collected on nine different occasions during 2002 and 2003.Whole-water samples from the discharge caused a significant androgenic response in the CV-1 cells and contained detectable concentrations of 17 alpha- and 17 beta-trenbolone.Further work is needed to ascertain the degree to which synthetic androgens such as trenbolone contribute to androgenic activity of feedlot discharges.