PT - JOURNAL ARTICLE AU - Nauck, Michael A. AU - Baller, Birgit AU - Meier, Juris J. TI - Gastric Inhibitory Polypeptide and Glucagon-Like Peptide-1 in the Pathogenesis of Type 2 Diabetes AID - 10.2337/diabetes.53.suppl_3.S190 DP - 2004 Dec 01 TA - Diabetes PG - S190--S196 VI - 53 IP - suppl 3 4099 - http://diabetes.diabetesjournals.org/content/53/suppl_3/S190.short 4100 - http://diabetes.diabetesjournals.org/content/53/suppl_3/S190.full SO - Diabetes2004 Dec 01; 53 AB - The incretin effect denominates the phenomenon that oral glucose elicits a higher insulin response than does intravenous glucose. The two hormones responsible for the incretin effect, glucose-dependent insulinotropic hormone (GIP) and glucagon-like peptide-1 (GLP-1), are secreted after oral glucose loads and augment insulin secretion in response to hyperglycemia. In patients with type 2 diabetes, the incretin effect is reduced, and there is a moderate degree of GLP-1 hyposecretion. However, the insulinotropic response to GLP-1 is well maintained in type 2 diabetes. GIP is secreted normally or hypersecreted in type 2 diabetes; however, the responsiveness of the endocrine pancreas to GIP is greatly reduced. In ∼50% of first-degree relatives of patients with type 2 diabetes, similarly reduced insulinotropic responses toward exogenous GIP can be observed, without significantly changed secretion of GIP or GLP-1 after oral glucose. This opens the possibility that a reduced responsiveness to GIP is an early step in the pathogenesis of type 2 diabetes. On the other hand, this provides a basis to use incretin hormones, especially GLP-1 and its derivatives, to replace a deficiency in incretin-mediated insulin secretion in the treatment of type 2 diabetes.