INS and obesity due to melanocortin 4 receptor deficiency: Because NAFLD is integral to the development of hyperinsulinemia and insulin resistance, and the HVAN regulates insulin secretion and action, we tested the hypothesis that lipid-induced hepatocyte depolarization changes the release of neurotransmitters to affect firing activity of the HVAN and drive the dysregulation of systemic glucose homeostasis common in obesity.