Investigations of the excretion of gamma-glutamyl-transpeptidase into the urine

The excretion of the enzyme gamma-glutamyl-transpeptidase and its isoenzymes into the urine was investigated in patients with renal diseases and compared with the excretion of the enzymes leucine-aminopeptidase and lactate-dehydrogenase. In animal experiments an increased excretion of these enzymes was found after autotransplantation. Increased excretion of gamma-glutamyl-transpeptidase was also found in patients with glomerulonephritis and in the polyuric phase of acute tubular necrosis, but not in cases of pyelonephritis and in the oliguric phase of acute tubular necrosis. The alterations of the isoenzyme pattern during diseases with increased enzyme excretion are in accordance with the hypothesis that the enzymes are liberated from the kidney tissue into the urine, and only a minority stems from the blood. Investigation of the excretion of gamma-glutamyl-transpeptidase and its isoenzymes into the urine seems to be of both scientific and clinical interest.