Transporter protein expression in Huh7 cells and human hepatocytes measured by LC-MS/MS. Data represent mean ± SD (n=3-4 independent experiments, except n=2 for OATP2B1 Huh7-1W and Huh7-2W, and MRP4 Huh7-4W). When protein expression was detected in less than one-half of the samples in a group, the group is expressed as not detectable (ND). ns, not significant; *, p<0.05; **, p<0.01; ***, p<0.001, significantly different from Huh7 cells cultured for 1 week (Huh7-1W).