Meeting Abstract

1.1  Thursday, Jan. 3  Thyroid Hormone Disruption Detection by Gene Expression Profiling SEARCY, B.T.*; BECKSTROM-STERNBERG, S.M.; STAFFORD, P.; SCHWENDIMAN, A.L.; SOTO-PENA, J.; OWEN, M.C.; FLIKKEMA, P.G.; PROPPER, C.R.; Northern Arizona University; Translational Genomics Research Institute; Arizona State University; Northern Arizona University; Northern Arizona University; Northern Arizona University; Northern Arizona UniversityT brian.searcy@nau.edu

Since the mid-twentieth century there has been a rapid increase in the production of synthetic chemicals; associated with this increased production has been the release of these compounds into the environment. It is becoming evident that these chemicals interfere with both endocrine and other physiological processes. Although the morphological and physiological outcomes of exposure for many compounds are becoming defined, the exact molecular mechanisms through which such changes are induced are harder to identify. Toxicogenomics now provides tools to begin to investigate changes in gene expression profiles due to exposure to environmental contaminants. We are beginning to use quantitative RT-PCR to determine whether some environmental pollutants can alter physiological processes through disruption of the thyroid hormone system. As a first step in developing this assay we have produced a gene expression profile of stages 51-54 (Nieuwkoop and Faber) Xenopus laevis tadpoles in response to 20 nM triiodo-l-thyroxine (T3) using Affymetrix X. laevis microarrays. We then compared our findings with two previous array studies examining T3 sensitive genes in Xenopus. Based on our analysis, we have identified multiple genes that are consistently T3 sensitive, and are targeting 10 specific genes for further validation as gene expression markers for endocrine disruption of the thyroid hormone system using a quantitative PCR based assay. This assay will provide a powerful new tool for rapidly screening compounds for potential thyroid system disrupting effects.