Increased Resting and Exercise-Induced Oxidative Stress in Young IDDM Men
- David E Laaksonen, MD,
- Mustafa Atalay, MD, MPH,
- Leo Niskanen, MD,
- Matti Uusitupa, MD,
- Osmo Hänninen, MD, PHD and
- Chandan K Sen, PHD
- Departments of Physiology, University of Kuopio Kuopio
- Clinical Nutrition, University of Kuopio Kuopio
- Department of Medicine, Kuopio University Hospital Kuopio, Finland
- Department of Molecular and Cell Biology, University of California at Berkeley Berkeley, California
- Address correspondence and reprint requests to David E. Laaksonen, MD, Department of Physiology, University of Kuopio, P.O. Box 1627, University of Kuopio, 70211 Kuopio, Finland. E-mail: laaksone{at}fokka.uku.fi
Abstract
OBJECTIVE To assess the effect of acute physical exercise on oxidative stress and glutathione redox status and the relation to physical fitness in otherwise healthy young men with IDDM.
RESEARCH DESIGN AND METHODS Nine men with IDDM (HbA1c 7.3 ± 1.7%), ages 21–30 years, and 13 matched control subjects exercised on a bicycle ergometer for 40 min at 60% of their maximal oxygen consumption (VO2max). Oxidative stress was assessed with plasma thiobarbituric acid reactive substance (TBARS) levels (an index of lipid peroxidation) and, in response to exercise, also glutathione redox status. For glutathione redox status, blood total glutathione (TGSH) and oxidized glutathione (GSSG) were determined. Blood samples were drawn immediately before and after exercise.
RESULTS Resting plasma TBARS levels were markedly elevated in diabetic patients (2.2 ± 0.7 vs. 0.9 ± 0.4 μumol/l; P = 0.0002). Mean blood TGSH was higher in diabetic subjects (1,203 ± 221 vs. 936 ± 156 mmol/l; P = 0.002), with no significant difference in GSSG or GSSG/TGSH values. Exercise increased plasma TBARS and blood GSSG by ∼50% in both groups. Resting plasma TBARS had a strong inverse correlation (r = −0.82; P = 0.006), and the exercise-induced percentage increase in TBARS had a strong positive correlation (r = 0.81, P = 0.008) with VO2max in diabetic subjects only.
CONCLUSIONS Glutathione redox status appears to be adequate in healthy young moderately active diabetic men. On the other hand, they demonstrated increased resting and postexercise oxidative stress as indicated by plasma TBARS. Although exercise acutely induces oxidative stress, in patients with diabetes, physical fitness may have a protective effect against oxidative stress.
- Received August 22, 1995.
- Revision received January 25, 1996.
- Accepted January 25, 1996.
- Copyright © 1996 by the American Diabetes Association
