Some natural ligands include fatty acids and eicosanoids (Xu et al., 1999), but PPAR structure also reveals selective lipophilic ligand binding pockets that are able to accommodate endogenous fatty acids and their derivatives as well as different chemical compounds, such as fibrates and thiazolidinediones (TZD) used to treat metabolic disorders, including hypertriglyceridemia or type 2 diabetes (Lalloyer and Staels, 2010). Here, PPARA is linked to metabolic disease.