Fig. 4.

Metformin enhances phosphorylation of CAR. Homogenate proteins from treated human hepatocytes were used for Western blot analysis of phosphorylated Thr38 hCAR, total hCAR, and β-actin as described in Materials and Methods. Specific treatments in this study include (A) DMSO (0.1%), PB (1 mM), or CITCO (1 µM) for 24 hours in human hepatocytes (HL#69, #77, and #81); (B) MET (1 mM) for 0, 15 minutes, 1 hour, 4 hours, and 24 hours in human hepatocytes (HL#77, #78, and #80); (C) MET (0.1, 0.5, 1 mM); and the combination of (D) MET with PB (1 mM) or (E) CITCO (1 µM) for 24 hours in human hepatocytes (HL#73, #74, and #82).