Altered antioxidant enzyme defences in insulin-dependent diabetic men with increased resting and exercise-induced oxidative stress.
Impaired antioxidant defences may predispose to the increased resting and exercise-induced oxidative stress found in patients with insulin-dependent diabetes mellitus (IDDM). We investigated major erythrocyte antioxidant enzyme activities at rest and in response to sustained, moderate intensity physical exercise in young diabetic men (n = 9) previously reported to have markedly elevated plasma lipid peroxidation and blood glutathione levels compared with control men (n = 13) (Laaksonen et al. 1996). At rest, erythrocyte glutathione reductase activity was 15% higher in the diabetic group (P = 0.049). Se-glutathione peroxidase and glutathione-S-transferase activities were similar in both groups. Red cell Cu, Zn-superoxide dismutase and catalase activities were lower in the IDDM group (P = 0.033 and P = 0.023, respectively). After 40 min of exercise at 60% of the subjects' peak oxygen consumption, Se-glutathione peroxidase activity rose by about 14% in the control group (P = 0.003), but not in the IDDM group (P = 0.47). Exercise did not cause significant changes in other enzyme activities in either group. To conclude, lower erythrocyte Cu, Zn-superoxide dismutase and catalase activity in young men with IDDM at rest may contribute to increased oxidative stress. On the other hand, increased glutathione reductase activity may represent a compensatory upregulation of glutathione homeostasis in response to increased oxidative stress. Upregulation of Se-glutathione peroxidase activity in response to physical activity appeared to be impaired in men with IDDM.
Atalay
M
M
Department of Physiology, University of Kuopio, Finland.
Laaksonen
D E
DE
Niskanen
L
L
Uusitupa
M
M
Hänninen
O
O
Sen
C K
CK
D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D001786:Blood Glucose / Q000378:metabolism; D002374:Catalase / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000201:enzymology; D004798:Enzymes / Q000097:blood*; D004912:Erythrocytes / Q000201:enzymology; D015444:Exercise / Q000502:physiology*; D018698:Glutamic Acid / Q000097:blood; D006801:Humans; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D012146:Rest / Q000502:physiology*; D013482:Superoxide Dismutase / Q000097:blood; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology
D000975:Antioxidants; D001786:Blood Glucose; D004798:Enzymes; D017392:Thiobarbituric Acid Reactive Substances; D018698:Glutamic Acid; D002374:Catalase; D013482:Superoxide Dismutase