Ying et al. suggested FGF21 could directly suppress oxidative stress and enhance endothelium-dependent vasorelaxation of aorta through the activation of calcium/calmodulin-dependent protein kinase kinase 2/AMPKα pathway in both T1DM and T2DM mice model, and that is independent of its glucose-lowering and insulin-sensitizing effects. This evidence concerns the gene FGF21 and type 2 diabetes mellitus.