[Restriction of Stress-induced Activation of Lipid Peroxidation by Small Doses of Thyroid Hormones]

The experiments on 57 female rats demonstrated that small doses of thyroid hormones (thyroidin) significantly (55-118%) restrict stress induced increase in the concentration of initial and terminal products of lipid peroxidation (LP) in the myocardium and in the blood plasma. After hormone injection stress decreases the activity of key antioxidant enzyme, superoxide dismutase of erythrocytes (SOD), to a lesser degree and increases the rate of malonyldialdehyde (MDA) production induced by Fe2+ in homogenates of the myocardium to the same degree as well in comparison with rats that had not been injected thyroidin. In normal rates thyroidin does not influence the concentration of products of LP, increases the activity of SOD and decreases increment of MDA induced by Fe2+ in homogenates of the myocardium. Thus, small doses of thyroid hormones restrict significantly stress induced activity of LP membranes, increasing the power of antioxidant systems both in the myocardium and in the organism.