ENZYME-ACTIVITIES IN HEPATIC VENOUS-BLOOD UNDER STRENUOUS PHYSICAL EXERCISE

In order to study the influence of physical exercise on liver function, healthy volunteers were subjected to a controlled major physical effort. Blood samples obtained by catheterization of hepatic vein during exercise were analyzed for activities of lactic dehydrogenase (thermostabile and thermolabile isoenzymes), alanine aminotransferase, sorbitol dehydrogenase, isocitrate dehydrogenase, alkaline phosphatase and creatine phosphokinase and these activities were compared with corresponding values in arterial blood samples taken simultaneously. Hepatic blood flow and O2 saturation of hepatic venous blood were measured. Physical exercise resulted both in diminished hepatic blood flow and a fall in hepatic venous O2 saturation. These changes were accompanied by release of liver specific enzymes, indicating that exhausting exercise may induce an increased hepatocyte membrane permeability in man.