ABCB1 and cholestasis: UDCA showed adequate ameliorative effects on cholestasis; the treated rats manifested a 2.1-fold higher level of UGT1A1 (p < 0.01), as well as 2.2-, 2.4-, 1.2-, 2.1-, and 1.5-fold higher levels of NTCP, MDR1, BSEP, OCT1, and OATP1A2 (p < 0.05), respectively, compared with the control group.