The role of incretins in insulin secretion

The notion that gut factors produced in response to nutrient ingestion are capable of stimulating the endocrine pancreas and consequently reducing glycemic levels was introduced more than 100 years ago. These gut factors were subsequently called incretins, and the augmented insulin response to nutrient given orally compared to nutrient administered intravenously was named "incretin effect." This chapter focuses on the mechanisms of the synthesis and actions of the incretin peptides, glucagon-like peptide 1, and glucosedependent insulinotropic polypeptide. In addition, alteration in incretin axis in type 2 diabetes and therapeutic relevance of these peptides will be highlighted. Finally, the role of incretin axis in diabetes remission after gastrointestinal surgeries for treatment of obesity will be briefly discussed.