We recently cloned the human, rabbit, rat, and mouse orthologs of a novel member of the
steroid/retinoid/thyroid hormone receptor family, which we have named the Pregnane X
Receptor (PXRs). The discovery and characterization of PXR has led to an increased
understanding of the molecular basis of many drug–drug interactions as well as a better
understanding of xenobiotic metabolism in general. The key insights into PXR action was
the finding that this nuclear receptor is linked to regulation of the cytochrome P450 3A …