It is also expressed in exocrine pancreatic microcirculation capillary endothelial cells/pericells and periislet capillaries and is involved in activating RAS circulation in systemic or local tissues.[10] ACE2 can improve the endothelial function of islet microvessels to protect islet function, ACE2/Ang1-7 can regulate glucose homeostasis by regulating GAD67/GABA signal transduction in β cells, improving β-cell function, and delaying the induction of diabetes.[11] ACE2 can reduce oxidative stress and apoptosis in islet cells and improve insulin secretion.[12]. This evidence concerns the gene GAD1 and diabetes mellitus.