IL1B and cholestasis: Research has shown that a marked reduction in NTCP mRNA levels contributes to inflammation-induced cholestasis in humans (Zollner et al., 2001), and that NTCP expression can be downregulated in isolated and cultured human hepatocytes following treatment with interleukin 6 (IL-6), IL-1β, or tumor necrosis factor-alpha (TNF-α) (Le Vee et al., 2008; Le Vee et al., 2009).