Susceptibility of glutatione and glutathione-related antioxidant activity to hydrogen peroxide in patients with type 2 diabetes: effect of glycemic control.
OBJECTIVE
The aim of the present study was to examine the susceptibility of glutathione (GSH) and glutathione related antioxidant enzymes to oxidation in type 2 diabetic patients with and without glycemic control.


METHODS
Erythrocyte glutathione level and activities of glutathione peroxidase (G-Px), glutathione reductase (G-Red) and glutathione S-transferase (GST) in controls, well controlled and poorly controlled type 2 diabetics were measured by spectrophotometric assays before and after the incubation in vitro with H2O2.


RESULTS
GSH level, G-Px and G-Red activities decreased but GST activity increased in the erythrocytes from all the groups after the incubation with H2O2. Percentage of decrease in GSH was independent from glycemic control, whereas the percentage of decreases in G-Px and G-Red was related to glycemic control. The percentage of increase in GST was found to be independent from diabetes.


CONCLUSIONS
GSH and GSH-related antioxidant enzymes in human erythrocytes are susceptible to oxidation, particularly, G-Px and G-Red which were found to be more susceptible to oxidation in erythrocytes from poorly controlled type 2 diabetic patients.
Department of Biochemistry, Cerrahpaşa Medical Faculty, Istanbul University, Istanbul, Turkey. stare63@yahoo.com
Yildiz
Y
Dinçer
Zeynep
Z
Alademir
Hasan
H
Ilkova
Tülay
T
Akçay
D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000201:enzymology; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D005260:Female; D005978:Glutathione / Q000097:blood*; D005979:Glutathione Peroxidase / Q000097:blood*; D005980:Glutathione Reductase / Q000097:blood*; D005982:Glutathione Transferase / Q000097:blood*; D006031:Glycosylation; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D011933:Reagent Kits, Diagnostic
D001786:Blood Glucose; D006454:Hemoglobins; D011933:Reagent Kits, Diagnostic; D006861:Hydrogen Peroxide; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D005978:Glutathione