Changes in metabolic processes in humans during a 120-day antiorthostatic hypokinesia

Abstract

The activities of organ- and tissue-specific diagnostically significant enzymes, including aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, alkaline phosphatase, total and prostatic acid phosphatase, glutamate dehydrogenase, choline esterase, amylase, lactate dehydrogenase, oxybutyrate dehydrogenase, and creatin phosphokinase (muscular and cardiac isoenzymes), as well as the concentrations of total cholesterol and the cholesterol of high- and low-density lipoproteins, the ratios of their concentrations, and the level of triglycerides, were studied during an experiment with 120-day antiorthostatic (−7°) hypokinesia (ANOH) in the blood of six volunteers (men, 21 to 36 years old). In addition, the indices of lipid peroxidation (LPO) and antioxidant activity were determined, including the concentrations of diene conjugates, malonic dialdehyde, Schiff bases and tocopherol, and the total antioxidant activity. It was found that a 120-day ANOH in this experiment did not result in the formation of deep metabolic shifts accompanied by unfavorable changes in organs and tissues. The changes in cholesterol metabolism during hypokinesia were expressed in the redistribution of cholesterol fractions with the dominance of atherogenic forms and a higher risk of atherogenesis. All of the observed metabolic changes were easily reversible and eliminated during the first month of the recovery period. No signs of a higher intensity of free-radical processes were observed during any of the examination periods due to activation of the antioxidant defense system.