Expression of LPS target genes in the lung and liver of wild-type (WT) and AHR−/− (KO) mice. Total RNA was extracted from the lung and liver of four to six mice per group after 3 and 6 h of LPS challenge and analyzed via real-time PCR for the expression of CYP1A1, COX-2, CEBPβ, RelB, IL-1β, IL-6, KC, IL-10, TNF-α, PAI-2, IDO-1 and IDO-2. The mRNA expression levels were normalized to β-actin. *Significantly different compared to corresponding tissue from control mice (p < 0.05); #significantly different from WT mice control or treated (p < 0.05).