Malondialdehyde, lipofuscin and activity of antioxidant enzymes during physical exercise in patients with essential hypertension

Design To clarify the role of oxidative damage in essential hypertension, l evels of lipid peroxidation products (malondialdehyde and lipofuscin) and a ctivity of antioxidant enzymes (superoxide dismutase and glutathione peroxi dase) were examined during a short period of physical exercise. Patients and methods We studied 11 male patients with mild to moderate esse ntial hypertension in World Health Organization classes I or II and 10 heal thy male controls. Physical exercise was performed on a bicycle ergometer a t graded intensities of 1.0, 1.5 and 2.0 W/kg body weight Plasma concentrat ions of lipofuscin, malondialdehyde, epinephrine, norepinephrine, insulin, free fatty acids and glucose were determined. Superoxide dismutase activity was analysed in erythrocytes and glutathione peroxidase activity in whole blood. Results Concentrations of lipofuscin and malondialdehyde were significantly elevated in hypertensive patients. Superoxide dismutase activity was not d ifferent between groups, while glutathione peroxidase activity was signific antly decreased in hypertensive subjects. During exercise, the concentratio n of malondialdehyde and antioxidant enzyme activities increased significan tly in both groups. No differences were found in absolute increases between the normotensive and hypertensive subjects. The levels of glucose, insulin and free fatty acids were similar in both groups. Basal concentrations of catecholamines and also the exercise-induced increases were lower in hypert ensive patients. Conclusions Our results indicate increased oxidative damage in patients wit h essential hypertension, which might be caused by a decrease in the activi ty of glutathione peroxidase, The ability of superoxide dismutase and gluta thione peroxidase to respond to increased production of reactive oxygen spe cies during a short period of physical exercise was not impaired in hyperte nsive subjects. J Hypertens 1999, 17:529-535 (C) Lippincott Williams & Wilk ins.