FGF21 and diabetes mellitus: Additionally, Zhang et al. found that FGF21 alleviates diabetes-related cardiac apoptosis by activating the extracellular signal-regulated kinase 1/2 (ERK1/2), mitogen-activated protein kinase 14 (p38 MAPK), and AMPK pathways in a mouse model of type 1 diabetes mellitus (T1DM) [122,124].