GCG and type 2 diabetes mellitus: Glucagon-like peptide-1 (GLP-1) has been reported to improve T2DM through the stimulation of insulin-secreting pancreatic β-cells (Kreymann et al., 1987; Buchwald et al., 2004), and the inhibition of glucagon-secreting pancreatic α-cells (Holst, 2004), and decreasing gastrointestinal motility (Meier et al., 2003) and body weight (Larsen et al., 2001).