[Histochemical characteristics of the activity of succinate dehydrogenase and cytochrome oxidase in certain tissues and organs of patients with thyrotoxicosis and animals with experimental thyroidin toxicosis].

The activity of succinic dehydrogenase and cytochromoxidase was studied histochemically in the peripheral blood leukocytes, the thyroid gland tissue and the skeletal muscles of the patients suffering from thyrotoxicosis. The activity of these enzymes is also determined in the blood leukocytes, the cardiac muscle, the liver and the skeletal muscles of the experimental animals given thyroidin in a dose of 0.1 g per 100 g of body weight in the course of 10 days. A marked elevation of the activity of the oxidative enzymes in the patients with an increase of the severity of thyrotoxicosis and in the animals after the thyroidin administration was noted. The absence of any changes in the succinic dehydrogenase and cytochromoxidase activity in the tissue of the skeletal muscles permitted to suppose that increase of the oxidative processes occurred primarily in the organs bearing a great functional load (the thyroid gland, liver, skeletal muscle, etc.).