Hydrogen peroxide alters mitochondrial activation and insulin secretion in pancreatic beta cells
| Autor: | Claes B. Wollheim, Pierre Maechler, Lan Jornot |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1999 |
| Předmět: |
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone
medicine.medical_specialty Carbohydrate metabolism Biology Mitochondrion Biochemistry Potassium Chloride Cell Line Islets of Langerhans/drug effects/metabolism/secretion Islets of Langerhans 03 medical and health sciences Internal medicine Potassium Chloride/pharmacology Insulin Secretion medicine Insulin Animals Oxidative Stress/drug effects/physiology Succinates/pharmacology Molecular Biology 030304 developmental biology Membrane potential ddc:616 Insulin/secretion 0303 health sciences Endoplasmic reticulum 030302 biochemistry & molecular biology Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone/pharmacology Succinates Depolarization Hydrogen Peroxide Cell Biology Glucose/pharmacology Mitochondria Rats Oxidative Stress Cytosol Kinetics Glucose Endocrinology Secretagogue Beta cell Mitochondria/drug effects/metabolism/ultrastructure Hydrogen Peroxide/pharmacology Signal Transduction |
| Zdroj: | Journal of Biological Chemistry, Vol. 274, No 39 (1999) pp. 27905-13 |
| ISSN: | 0021-9258 |
| Popis: | The effects of a transient exposure to hydrogen peroxide (10 min at 200 microM H(2)O(2)) on pancreatic beta cell signal transduction and insulin secretion have been evaluated. In rat islets, insulin secretion evoked by glucose (16.7 mM) or by the mitochondrial substrate methyl succinate (5 mM) was markedly blunted following exposure to H(2)O(2). In contrast, the secretory response induced by plasma membrane depolarization (20 mM KCl) was not significantly affected. Similar results were obtained in insulinoma INS-1 cells using glucose (12.8 mM) as secretagogue. After H(2)O(2) treatment, glucose no longer depolarized the membrane potential (DeltaPsi) of INS-1 cells or increased cytosolic Ca(2+). Both DeltaPsi and Ca(2+) responses were still observed with 30 mM KCl despite an elevated baseline of cytosolic Ca(2+) appearing approximately 10 min after exposure to H(2)O(2). The mitochondrial DeltaPsi of INS-1 cells was depolarized by H(2)O(2) abolishing the hyperpolarizing action of glucose. These DeltaPsi changes correlated with altered mitochondrial morphology; the latter was not preserved by the overexpression of the antiapoptotic protein Bcl-2. Mitochondrial Ca(2+) was increased following exposure to H(2)O(2) up to the micromolar range. No further augmentation occurred after glucose addition, which normally raises this parameter. Nevertheless, KCl was still efficient in enhancing mitochondrial Ca(2+). Cytosolic ATP was markedly reduced by H(2)O(2) treatment, probably explaining the decreased endoplasmic reticulum Ca(2+). Taken together, these data point to the mitochondria as primary targets for H(2)O(2) damage, which will eventually interrupt the transduction of signals normally coupling glucose metabolism to insulin secretion. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|