ABCC4 and cholestasis: However, animal studies have shown that FXR-deficient mice are protected from cholestasis [122] and there is evidence that FXR activation might inhibit the expression activity of Multidrug Resistance Protein 4 (MRP4) [123], raising some concerns over the potential utility of FXR agonism in cholestasis, while these animal studies might support the development of anti-FXR therapies in cholestasis [124,125].