PARENT SESSION

(P054) Development and validation of a time-sensitive, field-deployable indicator of low dose environmental estrogen exposure.

Lehr, Randy^*,1, Swackhamer, Deborah¹, Ankley, Gerald², Denslow, Nancy³, ¹ University of Minnesota, Minneapolis, MN, USA² US Environmental Protection Agency, Mid-Continent Ecology Division, Duluth, MN, USA³ University of Florida, Gainesville, FL, USA

ABSTRACT- This study will develop and validate a time-sensitive, field-deployable, indicator of low-dose environmental estrogen (EE) exposure to be utilized in the harbors and estuaries of the Great Lakes. Previous studies have utilized vitellogenin (Vtg) protein and Vtg mRNA induction in caged fathead minnows (Pimephales promelas) as an indicator of EE exposure. These studies, however, have utilized site-specific, time-intensive designs, often exposing the fish to elevated EE doses. To utilize Vtg mRNA induction in caged fathead minnows to rapidly assess potential EE exposure across a variety of sites, Vtg mRNA induction must be validated as a time and dose-sensitive endpoint. To validate fathead minnow Vtg mRNA induction fathead minnows were exposed in situ to a series of low doses of 17-estradiol (E2) across a variety of ambient conditions. Fathead minnows were exposed to 10, 1 and 0.1 ng/L E2 measuring the time-to induction of Vtg mRNA and protein across three expected ambient temperatures 15, 20 and 25o C. To increase the sensitivity of this endpoint Vtg mRNA was measured using real-time, reverse-transcription polymerase chain reaction (RT-RT-PCR) to amplify the mRNA signal.

Key words: Pimephales promelas, 17-estradiol, RT-RT-PCR, Ecological Indicator