The effects of glucagon-like peptide-1 on the beta cell.
Type 2 diabetes is a progressive disease characterized by insulin resistance and impaired beta-cell function. Treatments that prevent further beta-cell decline are therefore essential for the management of type 2 diabetes. Glucagon-like peptide-1 (GLP-1) is an incretin hormone that is known to stimulate glucose-dependent insulin secretion. Furthermore, GLP-1 appears to have multiple positive effects on beta cells. However, GLP-1 is rapidly degraded by dipeptidyl peptidase-4 (DPP-4), which limits the clinical relevance of GLP-1 for the treatment of type 2 diabetes. Two main classes of GLP-1-based therapies have now been developed: DPP-4 inhibitors and GLP-1 receptor agonists. Liraglutide and exenatide are examples of GLP-1 receptor agonists that have been developed to mimic the insulinotropic characteristics of endogenous GLP-1. Both have demonstrated improved beta-cell function in patients with type 2 diabetes, as assessed by homoeostasis model assessment-B analysis and proinsulin : insulin ratio. Additionally, liraglutide and exenatide are able to enhance first- and second-phase insulin secretion and are able to restore beta-cell sensitivity to glucose. Preclinical studies have shown that both liraglutide and exenatide treatment can increase beta-cell mass, stimulate beta-cell proliferation, increase beta-cell neogenesis and inhibit beta-cell apoptosis. Clinical studies are needed to confirm these findings in humans. Replication of these data in humans could have important clinical implications for the treatment of type 2 diabetes.
Vilsbøll
T
T
Department of Internal Medicine, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark. t.vilsboll@dadlnet.dk
D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism; D000077270:Exenatide; D052216:Glucagon-Like Peptide 1 / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D054795:Incretins / Q000627:therapeutic use*; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism; D000069450:Liraglutide; D010455:Peptides / Q000627:therapeutic use*; D014688:Venoms / Q000627:therapeutic use*
D007004:Hypoglycemic Agents; D054795:Incretins; D010455:Peptides; D014688:Venoms; D000069450:Liraglutide; D052216:Glucagon-Like Peptide 1; D000077270:Exenatide