FGF21 and type 2 diabetes mellitus: On the other hand, FGF21 also has significant effects on hepatic glucose homeostasis and hepatic insulin sensitivity in T2DM mice.12 Moreover, FGF21 has a high basal expression in pancreatic islets of mice21, 22, 23 as well as enhances β‐cell function and survival in diabetic mice.24, 25 Importantly, exogenous FGF21 replenishment has been shown to increase insulin secretion and content in pancreatic islets isolated from diabetic rodents.25 However, the role of pancreatic FGF21 in the maintenance of pancreatic islet morphology and function remains obscure.