While these preliminary findings must be confirmed in larger samples of T2D islets, they support the conclusions that 1) suppression of SST secretion from islet δ-cells acts as a permissive signal for counterregulatory glucagon release, and 2) this permissive signal may be compromised in T1D and advanced T2D (Vergari et al., 2020). This evidence concerns the gene GCG and type 2 diabetes mellitus.