[Gamma-glutamyltranspeptidase (gamma-GT)].

gamma-GT is a membrane-bound enzyme which plays a role in the metabolism of glutathione and facilitates amino-acid transport. gamma-GT is located in several tissues such as the kidney, pancreas and liver. Serum gamma-GT activity is induced by hepatobiliary diseases, especially alcoholic liver diseases and cholestasis, not by renal diseases. Isoenzymes specific for hepatocellular carcinoma are demonstrated by electrophoresis. A new method of measuring serum gamma-GT specific for hepatocellular carcinoma was recently reported.