GCG and type 2 diabetes mellitus: Glucagon-like peptide 1 (GLP1) is an endogenous intestinal peptide hormone responsible for the stimulation of insulin secretion and the inhibition of glucagon release [83], and GLP1 analogues (such as liraglutide and exenatide) have been extensively used in the treatment of type 2 diabetes (T2D) [81,82].