TABLE 4 Effect of IL-1β on transporter expression in PXR+/+ versus PXR-/- mice Mice (n = 4–6) were injected with saline vehicle control or 10,000 U of IL-1β (i.p.) and were sacrificed 6 h later. Levels of mRNA were determined by RT-PCR as described under Materials and Methods. Data is presented as the percentage of controls, mean (S.E.M.).