[Effect of adaptation to medium altitude (1600 m) on the stability of parameters of lipid metabolism of the myocardium during stress].

The myocardial levels of total lipids and blood free fatty acids were measured in rats exposed to emotional pain, hypoxic, norepinephrine-, and rausedil-induced stresses. The indices of anti-radical protection and superoxide-inhibitory activity of the heart were calculated. Various stresses in early adaptation to the mountain climate were found to enhance lipid peroxidation with a lower activity of antioxidative enzymes, total lipids, and substantially increased the formation of nonesterified fatty acids. As steady-state mountain adaptation during 30-40 days made lipid peroxidation return to the baseline, the total amount of lipids decreased, and the level of nonesterified fatty acids increased. The nonspecific stresses caused by specific stressors both in low- and high-lands caused homeostatic changes. The antioxidative enzymes became more resistant to stress-induced prooxidants, their activity enhanced, suggesting that anti-radical protection is effected under the mountain conditions. The myocardium becomes resistant to any stress due to its leading and adaptive accumulation of antioxidative enzymes that inhibit the stress-induced enhancement of lipid peroxidation.