Figure 4B illustrates the model results in T1D. To approximate this setting, mI in Equation 1 and the basal insulin level were set to 0. Without any source of insulin, the α-cell side of the model will progress as if β-cells were not present. The calculated glucagon secretion rate is 1.5 × 10-4 mg/min and the calculated pancreatic glucagon concentration is 30-fold higher than in the normal pancreas, in line with the hyperglucagonemia observed in patients with diabetes (47). This evidence concerns the gene GCG and diabetes mellitus.