The most relevant BA-activated NRs for regulation of hepatobiliary homeostasis, bile secretion, and, thereby understanding and treating cholestasis, include the farnesoid X receptor (FXR, NR1H4),7 pregnane X receptor (PXR, NR1I2),8,9 and vitamin D receptor (VDR, NR1I1).10 The gene discussed is NR1H4; the disease is cholestasis.