Document Detail


Cortical and hippocampal mitochondria bioenergetics and oxidative status during hyperglycemia and/or insulin-induced hypoglycemia.
MedLine Citation:
PMID:  20620209     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study was undertaken to evaluate the effects of streptozotocin (STZ)-induced hyperglycemia and insulin-induced hypoglycemia in cortical and hippocampal mitochondria bioenergetics and oxidative status. For that purpose we used, citrate (vehicle)-treated Wistar rats, STZ-treated rats [i.p., 50mg/kg body weight] and STZ-treated rats injected with insulin [s.c., dose adjusted to blood glucose levels] 1h prior to sacrifice to induce an acute episode of hypoglycemia. Several parameters were analyzed: respiratory chain, phosphorylation system, thiobarbituric acid reactive substances (TBARS) levels, hydrogen peroxide (H(2)O(2)) production rate, and non-enzymatic and enzymatic antioxidant defenses. Cortical mitochondria from insulin-induced hypoglycemic rats present a significant decrease in the ADP/O index, a significant increase in the repolarization lag phase and a decrease in GSH/GSSG ratio when compared with STZ and control mitochondria. Both STZ-induced diabetes and insulin-induced hypoglycemia promote a significant increase in TBARS levels and a decrease in glutathione disulfide reductase activity. Diabetic cortical mitochondria present a significant decrease in glutathione peroxidase (GPx) activity compared to control mitochondria. In turn, insulin-induced hypoglycemia induced a significant increase in GPx and manganese superoxide dismutase (MnSOD) activities. In hippocampal mitochondria, insulin-induced hypoglycemia increases the respiratory control ratio whereas both situations, hyper- and hypoglycemia, potentiate H(2)O(2) production and decrease the activity of MnSOD. These results suggest that the poor glycemic control that occurs in type 1 diabetic patients undergoing insulin therapy may have detrimental effects in brain areas involved in learning and memory.
Authors:
Susana Cardoso; Maria S Santos; Raquel Seiça; Paula I Moreira
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-07-08
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1802     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-09-20     Completed Date:  2010-12-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  942-51     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier B.V. All rights reserved.
Affiliation:
Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Glucose / metabolism
Cerebral Cortex / metabolism*
Diabetes Mellitus, Experimental / blood,  chemically induced,  metabolism
Energy Metabolism
Glutathione / metabolism
Glutathione Disulfide / metabolism
Glutathione Peroxidase / metabolism
Hemoglobin A, Glycosylated / metabolism
Hippocampus / metabolism*
Hyperglycemia / blood,  chemically induced,  metabolism*
Insulin
Male
Membrane Potential, Mitochondrial
Mitochondria / metabolism*
Oxidation-Reduction
Oxidative Phosphorylation
Rats
Rats, Wistar
Reactive Oxygen Species / metabolism
Streptozocin
Superoxide Dismutase / metabolism
Thiobarbituric Acid Reactive Substances / metabolism
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Hemoglobin A, Glycosylated; 0/Reactive Oxygen Species; 0/Thiobarbituric Acid Reactive Substances; 11061-68-0/Insulin; 18883-66-4/Streptozocin; 27025-41-8/Glutathione Disulfide; 70-18-8/Glutathione; EC 1.11.1.9/Glutathione Peroxidase; EC 1.15.1.1/Superoxide Dismutase

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