ABSTRACT
In the gastrointestinal tract we produce hormones, called incretins, in response to food ingestion with a direct effect on pancreatic ß and α cell improving the insulin and glucagon response to glucose. The effect consisting in a greater secretion of insulin with a glucose stimulus from the gut or IV injection is called "the incretin effect." The main incretins are: glucagon like peptide-1 (GLP1) and glucose-dependent insulinotropic peptide (GIP). The action of both incretins is very short due to a rapid inhibition in the circulation by an enzyme dipeptylpeptidase IV (DPP4). In type 2 diabetics, the incretin effect is altered and can be improved by elaboration of a GLP1 resistant to the action of DPP4 (GLP1 analogs) or by direct inhibition of DPP4 producing better effect of native GLP1 and GIP. We have exenatide a derivative from exendin 4, and liraglutide very similar to the native human GLP1. Three inhibitors of DPP4: sitagliptin, and vildagliptin and saxagliptin produce a prolonged inhibition of DPP4 and as a consequence increased effect of native incretins with better control of fasting and postprandial glucose and improve on A1c with a very few hypoglycemic events.
