Incretins and other peptides in the treatment of diabetes.
Glucagon-like peptide-1 (7-36) amide (GLP-1) is a gut hormone, released postprandially,which stimulates insulin secretion and insulin gene expression as well as pancreatic B-cell growth. Together with glucose-dependent insulinotropic polypeptide (GIP), it is responsible for the incretin effect which is the augmentation of insulin secretion following oral administration of glucose. Patients with Type 2 diabetes have greatly impaired or absent incretin-mediated insulin secretion which is mainly as a result of decreased secretion of GLP-1. However,the insulinotropic action of GLP-1 is preserved in patients with Type 2 diabetes,and this has encouraged attempts to treat Type 2 diabetic patients with GLP-1.GLP-1 also possesses a number of potential advantages over existing agents for the treatment of Type 2 diabetes. In addition to stimulating insulin secretion and promoting pancreatic B-cell mass, GLP-1 suppresses glucagon secretion,delays gastric emptying and inhibits food intake. Continuous intravenous and subcutaneous administration significantly improves glycaemic control and causes reductions in both HbA1c and body weight. However, GLP-1 is metabolized extremely rapidly in the circulation by the enzyme dipeptidyl peptidase IV(DPP-IV). This is the probable explanation for the short-lived effect of single doses of native GLP-1, making it an unlikely glucose-lowering agent. The DPP-IV resistant analogue, exenatide, has Food and Drug Administration (FDA) approval for the treatment of Type 2 diabetes and selective DPP-IV inhibitors are underdevelopment. Both approaches have demonstrated remarkable efficacy in animal models and human clinical studies. Both are well tolerated and appear to have advantages over current therapies for Type 2 diabetes, particularly in terms of the effects on pancreatic B-cell restoration and potential weight loss.
Todd
J F
JF
Department of Metabolic Medicine, Imperial College London, Hammersmith Hospital, London, UK.
Bloom
S R
SR
D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism; D000077270:Exenatide; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism / Q000627:therapeutic use*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism / Q000627:therapeutic use; D014688:Venoms / Q000378:metabolism / Q000627:therapeutic use; D015431:Weight Loss / Q000187:drug effects*
D007004:Hypoglycemic Agents; D010455:Peptides; D014688:Venoms; D052216:Glucagon-Like Peptide 1; D000077270:Exenatide; D018819:Dipeptidyl Peptidase 4