Effects of the Feedlot Contaminant 17-Trenbolone on Reproductive Endocrinology of the Fathead Minnow
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- 作者：Kathleen M. Jensen ; Elizabeth A. Makynen ; Michael D. Kahl ; and Gerald T. Ankley
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：May 1, 2006
- 年：2006
- 卷：40
- 期：9
- 页码：3112 - 3117
- 全文大小：115K
- 年卷期：v.40,no.9(May 1, 2006)
- ISSN：1520-5851
文摘
Trenbolone acetate is a growth promoter widely used forbeef production in the U.S. Two biologically activemetabolites of the acetate, 17
ta2.gif" BORDER=0 ALIGN="middle">- and 17
-trenbolone, areligands of vertebrate androgen receptors and comparativelystable in the waste of treated animals. Both have beendetected in surface water associated with beef feedlots,suggesting a potential risk to aquatic animals. In previouswork we evaluated the effects of ta2.gif" BORDER=0 ALIGN="middle">-trenbolone onreproductive endocrinology of the fathead minnow(Pimephales promelas) in a 21-day test. The purpose ofthe present study was to conduct a similar set of experimentswith -trenbolone which, based on binding to mammalianandrogen receptors, was expected to be less potentthan ta2.gif" BORDER=0 ALIGN="middle">-trenbolone. Fecundity of the fish was significantlyreduced by -trenbolone with an EC50 (95% confidenceinterval) of 0.011 (0.007-0.016) 
tities/mgr.gif">g/L. In females, -trenbolonereduced plasma vitellogenin and steroid concentrationsand also induced the production of dorsal nuptial tubercles,structures normally present only in spawning males.Overall, effects of -trenbolone on the reproductive systemof the fish were qualitatively and quantitatively quitesimilar to those caused by ta2.gif" BORDER=0 ALIGN="middle">-trenbolone. Part of this similaritymight arise from the fact that a substantial amount ofthe -trenbolone appeared to be converted to ta2.gif" BORDER=0 ALIGN="middle">-trenboloneby the fish. Tissue concentrations of the ta2.gif" BORDER=0 ALIGN="middle">-isomer wereconsistently similar to or greater than concentrations of-trenbolone, despite the fact that no ta2.gif" BORDER=0 ALIGN="middle">-trenbolone wasdetected in the exposure water. The present studydemonstrates the importance of considering both - andta2.gif" BORDER=0 ALIGN="middle">-trenbolone in assessing the potential ecological risk ofandrogens associated with beef feedlot discharges.
ta2.gif" BORDER=0 ALIGN="middle">- and 17-trenbolone, areligands of vertebrate androgen receptors and comparativelystable in the waste of treated animals. Both have beendetected in surface water associated with beef feedlots,suggesting a potential risk to aquatic animals. In previouswork we evaluated the effects of ta2.gif" BORDER=0 ALIGN="middle">-trenbolone onreproductive endocrinology of the fathead minnow(Pimephales promelas) in a 21-day test. The purpose ofthe present study was to conduct a similar set of experimentswith -trenbolone which, based on binding to mammalianandrogen receptors, was expected to be less potentthan ta2.gif" BORDER=0 ALIGN="middle">-trenbolone. Fecundity of the fish was significantlyreduced by -trenbolone with an EC50 (95% confidenceinterval) of 0.011 (0.007-0.016) tities/mgr.gif">g/L. In females, -trenbolonereduced plasma vitellogenin and steroid concentrationsand also induced the production of dorsal nuptial tubercles,structures normally present only in spawning males.Overall, effects of -trenbolone on the reproductive systemof the fish were qualitatively and quantitatively quitesimilar to those caused by ta2.gif" BORDER=0 ALIGN="middle">-trenbolone. Part of this similaritymight arise from the fact that a substantial amount ofthe -trenbolone appeared to be converted to ta2.gif" BORDER=0 ALIGN="middle">-trenboloneby the fish. Tissue concentrations of the ta2.gif" BORDER=0 ALIGN="middle">-isomer wereconsistently similar to or greater than concentrations of-trenbolone, despite the fact that no ta2.gif" BORDER=0 ALIGN="middle">-trenbolone wasdetected in the exposure water. The present studydemonstrates the importance of considering both - andta2.gif" BORDER=0 ALIGN="middle">-trenbolone in assessing the potential ecological risk ofandrogens associated with beef feedlot discharges.