Peroxisome proliferator-activated receptor-alpha (PPARalpha)activators, fish oil feeding, or fibrate administration up-regulated mitochondrial uncoupling protein (UCP2) mRNA expression in mouse liver by 5-9-fold, whereas tumor necrosis factor-alpha (TNFalpha) also up-regulated UCP2 in liver. In this study, the mechanisms for PPARalpha activators-induced up-regulation of UCP2 mRNA, related to TNFalpha and reactive oxygen ... More