DPP4 and type 2 diabetes mellitus: Thus, enhancing incretin action by providing physiological dosages of GLP-1 through GLP-1 receptor agonists or dipeptidyl peptidase-4 (DPP-4) inhibitors (incretin enhancers) is an effective treatment for patients with T2DM (Drucker and Nauck, 2006; Gilbert and Pratley, 2020).