In the setting of diabetes, the reduced detecting and regulatory power of δ-cells could result in “a chaotic islet community”: insufficient somatostatin secretion/signaling leads to oversecretion of insulin or glucagon and glucose volatility; oversensitive δ-cells or oversecretion of somatostatin, on the other hand, effectively paralyze hormone secretion from β-cells and α-cells, leading to hyperglycemia or hypoglycemia. This evidence concerns the gene GCG and diabetes mellitus.