The abnormalities in glucagon secretion in T2DM include both loss of adequate suppression under hyperglycemic conditions (Cryer, 2002, Cryer, 2008, Cryer et al., 2003, Dunning et al., 2005, D’Alessio, 2011, Unger and Cherrington, 2012) and insufficient release during episodes of hypoglycemia (Gerich et al., 1973, Bolli and Perriello, 1990, Shamoon et al., 1994). This evidence concerns the gene GCG and type 2 diabetes mellitus.