Enzyme activities in hepatic venous blood under strenuous physical exercise.

In order to study the influence of physical exercise on liver function, experiments were performed in healthy volunteers subjected to controlled major physical effort. Blood samples obtained by catheterization of hepatic vein during exercise were analyzed for activities of LD (thermostabile and thermolabile isoenzymes), AlAT, SDH, ICD, AP and CPK, and these activities were compared with corresponding values in arterial blood samples taken simultaneously. Hepatic blood flow and oxygen saturation of hepatic venous blood were measured. Physical exercise resulted both in diminished hepatic blood flow and a fall in hepatic venous oxygen saturation. These changes were accompanied by release of liver specific enzymes, indicating that exhausting exercise may induce an "increased hepatocyte membrane permeability" in man.