The reduced expression of Ntcp and Bsep in EE-induced cholestasis and restoration of Bsep by the UDCA treatment, consistent with the previous reports [21,26,27,28], could be underlying mechanisms for recovery of bile flow and total bile salts in the plasma and bile after the UDCA treatment (Table 1 and Table 2). This evidence concerns the gene ABCB11 and cholestasis.