The Incretin Axis-Revisiting the Basics: A Review

Abstract

Incretin effect is the augmented insulin secretion in response to oral glucose load as compared to intravenous glucose. This incretin axis that has been demonstrated in the gut is mainly mediated by two important gut hormones, namely glucagon-like peptide-1(GLP-1) and glucose dependent insulinotropic polypeptide (GIP). These hormones improve insulin secretion by glucose dependent pathways conferring unique glycemic benefits and safety that has led to their development as pharmacological agents as GLP-1 and dipeptidyl peptidase 4 inhibitors (DPP4-i). Additionally, they have been found to have pleotropic benefits suggesting their presence beyond the gut. This review deals with the advances in the physiology of these incretins and the presence of incretin axes elsewhere.