Development and validation of in vitro bioassays for thyroid hormone receptor mediated endocrine disruption

Thyroid hormones regulate crucial processes in vertebrates such as reproduction, development and energy metabolism. Endocrine disruption via the thyroid hormone system is gaining more attention both from scientists and regulators, because of the increasing incidence of hormone-related cancers and developmental defects, and the requirement that newly marketed compounds are tested for thyroid hormone disruption. To reduce the number of experimental animals used and to increase the insight into the mechanisms of toxic interference with the thyroid hormone receptor function, we developed and validated functional in vitro bioassays for thyroid hormone receptor-mediated toxicity. These assays enable quick identification and quantification of specific thyroid hormone receptor disrupting potency of compounds and contribute to the further establishment of a battery of in vitro tests for hazard identification of thyroid active compounds.