GLP1R and diabetes mellitus: Several second-line drugs are available, including conventional drugs such as sulfonylureas or glinides (SU), and newer agents for diabetes treatment such as dipeptidyl peptidase-4 inhibitors (DPP-4i), sodium-glucose cotransporter 2 inhibitors (SGLT2i), and glucagon-like peptide-1 receptor agonists (GLP-1-RA).4