title: G proteins and modulation of insulin secretion.
abstract: Guanine nucleotide-binding proteins (G proteins) are critically important mediators of many signal-transduction systems. Several important sites regulating stimulus-secretion coupling and release of insulin from pancreatic beta-cells are modulated by G proteins. Gs mediates increases in intracellular cAMP associated with hormone-induced stimulation of insulin secretin. Gi mediates decreases in intracellular cAMP caused by inhibitors of insulin secretion, e.g., epinephrine, somatostatin, prostaglandin E2, and galanin. G proteins also regulate ion channels, phospholipases, and distal sites in exocytosis. Cholera and pertussis toxins irreversibly ADP ribosylate G proteins and are important tools that can be used both to manipulate G-protein-dependent modulators of insulin secretion and detect and quantify G proteins by electrophoretic techniques. The stage is set to pursue these initial observations in greater depth and ascertain whether G-protein research will provide important new insights into normal and abnormal regulation of insulin secretion.
authors.affiliation: Diabetes Center, University of Minnesota, Minneapolis.
authors.forename: R P
authors.initials: RP
authors.lastname: Robertson
authors.forename: E R
authors.initials: ER
authors.lastname: Seaquist
authors.forename: T F
authors.initials: TF
authors.lastname: Walseth
mesh_terms: D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D015398:Signal Transduction
chemical_list: D007328:Insulin; D019204:GTP-Binding Proteins