Recently, estradiol-17β-D-glucuronide inhibited the expression of multidrug resistance-associated protein 2 (MRP2) at both transcriptional and post-transcriptional levels in the capillaries of hepatocytes in experimental cholestasis rats, suggesting a close relationship between genetic factors and hormones in the pathogenesis of ICP (Stieger et al., 2000). This evidence concerns the gene ABCC2 and cholestasis.