PPAR (Peroxisome proliferator-activated receptor) is a member of the nuclear hormone receptor superfamily and functions as a transcriptional activator. PPARα is preferentially expressed in liver, skeletal muscle, heart and kidney. PPARα is involved in regulation of lipid homeostasis. Its ligands include fatty acids, NSAIDs, prostaglandins, leukotriene B4, etc. PPARα transcriptionally regulates a variety of genes for enzymes and proteins involved in fatty acid metabolism and oxidation.