Effects of PPAR agonists on iNOS protein expression in J774 macrophages. Cells were stimulated with lipopolysaccharide (LPS) and treated with increasing concentrations of fenofibrate (a), muraglitazar (b) or GW1929 (c). After 24 h incubation, proteins were extracted and the levels of inducible nitric oxide synthase (iNOS) protein were analysed by Western blotting. β-actin was used as a loading control. Results represent the mean + SEM of three experiments, from which one representative Western blot is shown. *P <0.05 and **P <0.01 as compared to cells treated with LPS alone.