Indeed, we found that despite increased blood glucagon and intramitochondrial levels of acetyl-CoA (essential activators of PC) [60] in starved rats, ammonia loading enhanced the NAD/NADH ratio (Figure 3); ADP level in mitochondria, a potent PC inhibitor [54], together with ATP deficiency led to a significant decrease in PC activity (65%, p < 0.001). This evidence concerns the gene GCG and hyperinsulinemic hypoglycemia, familial, 4.