Figure 1: Sirt1-mediated regulation of metabolism in different tissues according to [92]. In pancreatic β-cells Sirt1 represses the expression of UCP2, thereby increasing insulin secretion, and Sirt 1 also regulates FoxOs, thereby protecting the β-cells against oxidative stress. In the liver Sirt1 regulates gluconeogenesis by activating PGC-1α. In muscle cells Sirt1 activates both PGC-1α and FoxO, thereby influencing mitochondrial biogenesis, respiration, and fatty acid oxidation. ATP: adenosine triphosphate; FoxO: forkhead box protein O; PGC-1α: peroxisome proliferator-activated receptor-γ coactivator 1 alpha; UCP: uncoupling protein 2.