Effects of PPAR agonists on IL-6 production in J774 macrophages. Cells were treated with increasing concentrations of fenofibrate (a), muraglitazar (b) or GW1929 (c) and stimulated with lipopolysaccharide (LPS). After 24 h incubation, IL-6 accumulated into the culture medium was measured by ELISA. Results represent the mean + SEM (n = 4). *P <0.05 and **P <0.01 as compared to cells treated with LPS alone.