Roles of Pyruvate, NADH, and Mitochondrial Complex I in Redox Balance and Imbalance in β Cell Function and Dysfunction

Figure 3

Mechanisms of β cell glucose sensing and insulin secretion. Shown is the first phase of insulin secretion stimulated by glucose derived ATP. When glucose levels are high, ATP levels are high, which depolarizes cell membranes, triggers the closure of the K_ATP channels, and induces opening of the Ca²⁺ channel. Consequently, insulin granules are infused with membranes and insulin is released. Complex I plays a key role in this process as ATP production is driven by its oxidation of NADH and transportation of electrons to CoQ that accompany proton pumping needed for ATP synthesis by complex V.