Incretin System: Recent Advances in Glucagon Like Peptide-1 and Dipeptidyl Peptidase-4 Inhibitors

The endogenous incretins, glucose-dependent insulinotropic polypeptideand Glucagon-like peptide, are peptide hormones secreted from endocrinecells in the small intestine. Glucagon-like peptide-1 stimulates insulinand suppresses glucagon secretion, delays gastric emptying, and reducesappetite and food intake, which explains the positive effect of incretinmimetics on weight. The incretins have also been shown to have a sustained improvement in glycemic control over three years. A wide range of cardiovascular benefits have also been claimed, such as lowering of blood pressure and postprandial lipids. Clinical trials with the incretin mimetic exenatide and liraglutide show reductions in fasting and postprandial glucose concentrations, and haemoglobin A1c (1–2%), associated with weight loss (2–5 kg). The most common adverse event associated with Glucagon-like peptide-1 receptor agonists is nausea, which lessens over time. Orally administered Dipeptidyl Peptidase-4 inhibitors reduce hemoglobin A1c by 0·5–1·0%, with few adverse effects and no weight gain. These new classes of anti-diabetic agents also expand β-cell mass in preclinical studies. However, long-term clinical studies are still needed to determine the benefits of incretin for the treatment of type 2 diabetes.Keywords: dipeptidyl pedptidase-4 inhibitors, glucagon-like peptide-1 RA,glucose-dependent insulino tropic polypeptide, increti