Progress in the studies on extra-islet effects of incretin

Incretin is defined as an intestinal hormone released in response to nutrient ingestion, which potentiates the glucose-induced insulin response. In human body, the incretin's effect is mainly induced by two peptide hormones, glucagon-like peptide-I (GLP-I)and glucose-dependent insulinotropic polypeptide (GIP). In order to fully evaluate the clinical advantages of novel agents based on incretin, this review introduces the islet actions of incretin in brief, and mainly focuses on the extra-islet effect of incretin. Key words: Incretin;  Glucagon-like peptide-I ;  Glucose-dependent insulinotropic polypeptide;  Diabetes mellitus, type 2