Farnesoid X receptor alpha (FXRα) is a member of the nuclear receptor superfamily involved in bile acid homeostasis, glucose metabolism, lipid homeostasis, and hepatic regeneration. NIEHS and NIH scientists with academic and industry collaborators evaluated substances identified in Tox21 HTS in vitro screens as FXRα agonists and antagonists using four experimental approaches. The study generally confirmed quantitative HTS in vitro results, provided data on protein:protein interactions and receptor docking, and translated those results to an in vivo system. A poster describing the study (Hamm et al.) was presented at the 2018 Society of Toxicology annual meeting.