title: Reactive oxygen species stimulate insulin secretion in rat pancreatic islets: studies using mono-oleoyl-glycerol.
abstract: Chronic exposure (24-72 hrs) of pancreatic islets to elevated glucose and fatty acid leads to glucolipoxicity characterized by basal insulin hypersecretion and impaired glucose-stimulated insulin secretion (GSIS). Our aim was to determine the mechanism for basal hypersecretion of insulin. We used mono-oleoyl-glycerol (MOG) as a tool to rapidly increase lipids in isolated rat pancreatic ß-cells and in the clonal pancreatic ß-cell line INS-1 832/13. MOG (25-400 µM) stimulated basal insulin secretion from ß-cells in a concentration dependent manner without increasing intracellular Ca(2+) or O(2) consumption. Like GSIS, MOG increased NAD(P)H and reactive oxygen species (ROS). The mitochondrial reductant ß-hydroxybutyrate (ß-OHB) also increased the redox state and ROS production, while ROS scavengers abrogated secretion. Diazoxide (0.4 mM) did not prevent the stimulatory effect of MOG, confirming that the effect was independent of the K(ATP)-dependent pathway of secretion. MOG was metabolized to glycerol and long-chain acyl-CoA (LC-CoA), whereas, acute oleate did not similarly increase LC-CoA. Inhibition of diacylglycerol kinase (DGK) did not mimic the effect of MOG on insulin secretion, indicating that MOG did not act primarily by inhibiting DGK. Inhibition of acyl-CoA synthetase (ACS) reduced the stimulatory effect of MOG on basal insulin secretion by 30% indicating a role for LC-CoA. These data suggest that basal insulin secretion is stimulated by increased ROS production, due to an increase in the mitochondrial redox state independent of the established components of GSIS.
authors.affiliation: Department of Medicine, Obesity Research Center, School of Medicine, Boston University, Boston, Massachusetts, United States of America.
authors.forename: Marylana
authors.initials: M
authors.lastname: Saadeh
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Ferrante
authors.forename: Ada
authors.initials: A
authors.lastname: Kane
authors.forename: Orian
authors.initials: O
authors.lastname: Shirihai
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Corkey
authors.forename: Jude T
authors.initials: JT
authors.lastname: Deeney
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000494:pharmacology; D000214:Acyl Coenzyme A / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D019852:Diacylglycerol Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D005989:Glycerides / Q000378:metabolism / Q000494:pharmacology*; D005990:Glycerol / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D052999:Quinazolinones / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000077185:Resveratrol; D013267:Stilbenes / Q000494:pharmacology
chemical_list: D000214:Acyl Coenzyme A; D005227:Fatty Acids; D005989:Glycerides; D007328:Insulin; D010880:Piperidines; D052999:Quinazolinones; D017382:Reactive Oxygen Species; D013267:Stilbenes; C058544:R 59949; C005953:monoolein; D019852:Diacylglycerol Kinase; D005947:Glucose; D005990:Glycerol; D000077185:Resveratrol; D002118:Calcium; D020155:3-Hydroxybutyric Acid