PPARG and obesity due to melanocortin 4 receptor deficiency: For example,PPARα-null or PPARγ-adiposeKO mice areprotected form insulin resistance and obesity caused by HFD.Studies in genetically long- or short-lived mice together with thestudies involving CR suggest that PPARs play an important role ininsulin action, lipid metabolism, immunity, and inflammation aswell as regulation of aging and longevity.