Targeting the glucagon receptor family for diabetes and obesity therapy.
Diabetes is a debilitating disease characterized by chronic hyperglycemia and is often associated with obesity. With diabetes and obesity incidence on the rise, it is imperative to develop novel therapeutics that will not only lower blood glucose levels, but also combat the associated obesity. The G protein-coupled receptors (GPCRs) for glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon are emerging as targets to treat both hyperglycemia and obesity. GIP is rapidly released from intestinal K-cells following food intake and stimulates glucose-dependent insulin secretion from β-cells and the storage of fat in adipocytes. Both GIP receptor agonists and antagonists have been demonstrated to display therapeutic potential to treat diabetes and obesity. Similar to GIP, GLP-1 is released from intestinal L-cells following food intake and potentiates glucose-dependent insulin secretion from β-cells. In addition, GLP-1 reduces glucagon levels, suppresses gastric emptying and reduces food intake. As such, GLP-1 receptor agonists effectively lower blood glucose levels and reduce weight. Finally, glucagon is released from α-cells and raises blood glucose levels during the fasting state by stimulating gluconeogenesis and glycogenolysis in the liver. Thus, molecules that antagonize the glucagon receptor may be used to treat hyperglycemia. Given the structural similarity of these peptides and their receptors, molecules capable of agonizing or antagonizing combinations of these receptors have recently been suggested as even better therapeutics. Here we review the biology of GIP, GLP-1 and glucagon and examine the various therapeutic strategies to activate and antagonize the receptors of these peptides.
Laboratory of Molecular and Cellular Medicine, Departments of Cellular and Physiological Sciences and Surgery, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
Young Min
YM
Cho
Catherine E
CE
Merchant
Timothy J
TJ
Kieffer
D000818:Animals; D019440:Anti-Obesity Agents / Q000494:pharmacology / Q000627:therapeutic use; D003920:Diabetes Mellitus / Q000188:drug therapy* / Q000503:physiopathology; D000067757:Glucagon-Like Peptide-1 Receptor; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use; D058990:Molecular Targeted Therapy / Q000379:methods; D009765:Obesity / Q000188:drug therapy* / Q000503:physiopathology; D010455:Peptides / Q000494:pharmacology / Q000627:therapeutic use; D011964:Receptors, Gastrointestinal Hormone / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000502:physiology; D018027:Receptors, Glucagon / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000502:physiology
D019440:Anti-Obesity Agents; C000593833:GLP1R protein, human; D000067757:Glucagon-Like Peptide-1 Receptor; D007004:Hypoglycemic Agents; D010455:Peptides; D011964:Receptors, Gastrointestinal Hormone; D018027:Receptors, Glucagon; C041086:gastric inhibitory polypeptide receptor