In vitro metabolism using rainbow trout liver S9 Summary report of the HESI Bioaccumulation Committee

Standard methods to assess bioaccumulation, such as QSARs, computer modeling, and the in vivo OECD 305 Test Guideline do not incorporate estimates of metabolism and are not valid for many chemical classes. In order to improve the in vitro assessment of bioaccumulation/bioconcentration assessment and enable concerted evaluations of thousands of commercial substances in a scientifically correct, timely and cost effective manner, this study was undertaken to examine and pre-validate the utility of rainbow trout S9 fractions to predict in vivo fish metabolism. The project aimed to standardize both the S9 isolation and incubation methodology and resulted in the development of a standardized method for both protocols that was recently published in Current Protocols. Funding was provided from the European Commission, Joint Research Center, Institute for Health and Consumer Protection, European Centre for the Validation of Alternative Methods (JRC/IHCP/ECVAM) and the European Chemical Industry Council (CEFIC), and five laboratories from North America, Europe, and Australia worked to validate this methodology, testing the approach with 15 different chemicals. The purpose of this report is to summarize and describe an overview of the project findings, limitations, lessons learned, and future recommendations for rainbow trout liver S9 metabolism assays. Raw data and additional details are available upon request by contacting Michelle Embry (membry@ilsi.org). ____________________________________________________________________________________