constitutive androstane receptor N uclear receptors constitute a large superfamily of transcription factors that regulate a diverse array of biological process, including development, differentiation, and neoplasia as well as energy and xenobiotic metabolism (1-3). The binding of specific ligands to nuclear receptors influences the recruitment of initial complex of coactivator proteins with histone acetyltransferase activity necessary for remodeling chromatin (1-3). Docking of several other cofactors results in the formation of a multiprotein coactivator complex, variously called thyroid hormone receptor-associated protein (TRAP)͞vitamin D receptorinteracting protein͞activator-recruited cofactor͞mediator complex, that facilitates interaction with RNA polymerase II and the general basal transcription machinery