Abstract:
Existing types of muscles differ not only structurally, but also metabolically (direction
of energy exchange, choice of biosubstrates, dependence on the action of mediators, hormones,
etc.). A number of studies have been devoted to the study of the impact of ionizing radiation on
metabolism in muscle tissue. After irradiation, thickened muscle cells with enlarged nuclei
appear in the heart muscle, the number of which does not decrease for 6 months, which
indicates a violation of nuclear-cytoplasmic relations in myocardial cells. Phosphoenolpyruvate
carboxykinase which ensures the utilization of cytoplasmic oxaloacetate and its transformation
into phosphoenolpyruvate, completes the initial stage of gluconeogenesis and can limit the rate
of gluconeogenesis from lactate. It should be emphasized that phosphoenolpyruvate
carboxykinase is more active in skeletal muscles, where the activity of pyruvate kinase and
lactate dehydrogenase is increased. The purpose of the work is to investigate the peculiarities of
the relationship between the terminal site of glycolysis and the initial segment of gluconeogenesis in the myocardium and skeletal muscles of animals irradiated at different
doses. The authors proved that in animals irradiated at a dose of 0.5 Gy, the activity of pyruvate
kinase in the myocardium and skeletal muscle increases compared to intact animals. In the
blood, on the contrary, there is a decrease in the activity of this enzyme compared to intact
animals. When animals are irradiated at a dose of 1.0 Gy, diametrically opposite changes are
observed. When animals are irradiated at a dose of 0.5 Gy, there is a slight decrease in the
activity of lactate dehydrogenase in the myocardium and blood against the background of an
increase in the activity of this enzyme in skeletal muscle. Irradiation of animals at a dose of 1.0
Gy leads to an acute increase in lactate dehydrogenase activity in the myocardium and skeletal
muscle. The data obtained revealed that in animals irradiated at a dose of 0.5 Gy, the activity of
phosphoenolpyruvate carboxykinase in skeletal muscle increases, while in cardiac muscle, on
the contrary, its activity decreases as well as in blood. With an increase in the radiation dose to
1.0 Gy, diametrically opposite changes in the activity of phosphoenolpyruvate carboxykinase
are observed. The authors concluded that outlined changes in the waу of intramuscular
glycolysis and gluconeogenesis reactions show the pathophysiologcal mechanisms of
biochemical supply restructuring as the result of ionizing irradiation influence. From the
fundamental point of view these results show the direction of pathophysiologically oriented
pharmacological correction of radiation-provoked muscle disturbances.
