Abstract

The enzyme Gamma-Glutamyl Transpeptidase (γ-GT, EC 2.3.2.2.) is distributed widely throughout the body, highest activities being present in the kidney, followed by pancreas, liver, spleen, and brain. It catalyses transfer of the gamma-glutamyl group from gama glutamyl peptides to other peptides or any of the common amino acids except proline. Since a group of Polish investigators first reported elevated γ-GT activity in sere of Patients with hepatic disease, a number of reports have appeared describing the conditions in which there is an elevated serum γ-GT activity. The level of γ-GT has been shown to be raised mainly in patients with hepato-biliary disease and to a lesser extent in a number of other conditions as Pancreatic, heart, neurologic, and renal diseases. As the Department of Clinical Pathology, Yonsei University Medical College, has recently purchased the autoanalyzer System 5 (Gilford Instrument Laboratories, Inc.), the rapid and_accurate determination of serum γ-GT activity has ben made possible. The author measured he activity in sera from the patients with a variety of diseases and 30 normal controls comprised of healthy medical students by using System 5. The results are as follows. 1. The average values of γ-GT for normal controls were 19.2 IU/L (range 8-33 IU/L) in male, and 16.5 IU/L (range 6-28 IV/L) in female, respectively. 2. Patients with all forms of hepato-biliary diseases had elevated serum γ-GT level. The highest activity was noted in patients with cholecystits or cholelithiasis. 3. Patients with primary hepatocellular and metastatic carcinomas had significantly elevated serum γ-GT level and higher increase rate than those of. any other enzyme tests. This may suggest the value of γ-GT as a screening test for neoplastic diseases of the liver. 4. Of all the patients studied, patients with carcinoma of pancreas revealed highest γ-GT values. 5. Patients with carcinomas except hepatocellular and pancreatic carcinomas did not reveal significant elevation of serum γ-GT activity. 6. In patients with bone diseases, γ-GT levels were within normal range in contrast to elevated alkaline phosphatase activities. 7. A portion of patients with neurologic diseases showed slightly elevated γ-GT level No significant change of γ-GT activity was noted in patients with renal failure. 8. In spite of the lack of specificity, it appears that the determination of γ-GT can indicate hepato-biliary dysfunction, especially used with other tests. 9. When the level of γ-GT is increased abruptly during the follow-up of a liver cirrhosis patient, the measurement of γ-GT may indicate the progress of liver cirrhosis or complication of hematoma, especially in a country like Korea which has a high incidence of liver.