Figure 2. The three peroxisome proliferator-activated receptor (PPAR) subtypes have their unique and overlapping ligand specificity. Activating PPARβ/δ in muscle tissue leads to mitochondrial biogenesis and increased fatty acid oxidation. While PPARα and γ are activated in the liver, vascular wall, and adipose tissue, apolipoprotein A-I (ApoA-I) and A-II, nitric oxide (NO), lipoprotein lipase, and adiponectin are increased, and toll-like receptor 4, leptin, and inflammatory cytokines repressed. These changes in combination contribute to improved insulin sensitivity and a normalized lipid profile with decreased TG, increased HDL, and decreased small dense LDL levels.