The causes of increase and decrease in gamma glutamyl transpeptidase
Last reviewed: 19.10.2021
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An increase in the activity of gamma glutamyl transpeptidase in the blood serum may be due to the following reasons.
- Increased synthesis as a result of the activation of enzymes that provide this process, alcohol and drugs.
- Damage to cell membranes under the influence of toxic agents, with ischemia and infectious liver damage.
- The release of the enzyme from binding to cell membranes as a result of the detergent effect of surface-active bile acids in all forms of cholestasis.
The change in the activity of gamma glutamyl transpeptidase in the blood serum is of great diagnostic importance in diseases of the liver and hepatobiliary tract. This enzyme is more sensitive to disorders in the liver cells than ALT, AST, alkaline phosphatase, glutamate dehydrogenase (Gldg), etc. The normal activity of this enzyme in bone diseases allows us to establish a source of increased activity of alkaline phosphatase.
Especially sensitive is the gamma glutamyl transpeptidase to the effect on the liver of long-term alcohol consumption. In alcohol abusers, the activity of gamma glutamyl transpeptidase in the blood serum correlates with the amount of alcohol taken. The test is especially valuable for controlling the treatment of alcoholism. Stopping alcohol intake reduces the enzyme activity by approximately 50% within 10 days.
Determination of gamma glutamyl transpeptidase activity is used to establish hepatotoxicity; it increases in 90% of cases of liver disease. In most cases, these patients in the blood at the same time increases activity and transaminase. An isolated increase in the activity of gamma glutamyl transpeptidase is observed in 6-20% of patients with pathology of the hepatobiliary system. Increase in activity of gamma glutamyl transpeptidase more than 3 times cause anticonvulsants, fatty degeneration of the liver and heart failure.
In acute hepatitis, the activity of gamma glutamyl transpeptidase increases earlier than the activity of AST and ALT. At the height of the disease, the activity of gamma glutamyl transpeptidase is lower (increased 2-5 times) than the activity of aminotransferases, and it normalizes much more slowly. This allows the use of gamma glutamyl transpeptidase to control the recovery of the patient.
The highest activity of gamma glutamyl transpeptidase (5-30 times higher than the reference interval) is observed with intra- and extrahepatic cholestasis. Several smaller values of enzyme activity are recorded in primary liver tumors. In malignant tumors of other localization, a gradual increase in the activity of gamma glutamyl transpeptidase indicates the presence of metastases in the liver. Gamma glutamyl transpeptidase activity can be used as a marker of pancreatic and prostate cancer, as it reflects remissions and relapses.
It should be noted again that the gamma glutamyl transpeptidase is multi-valued in a diagnostic sense. At least 5 processes increase its activity: cytolysis, cholestasis, alcohol intoxication, tumor growth in the liver, drug intoxication. The etiological diversity of the mechanisms for increasing gamma glutamyl transpeptidase requires a very careful and thorough assessment of the causes of hyperfermentemia. The detection of high activity of gamma glutamyl transpeptidase forces us to look for the cause of this increase. As a "screening" test and a method for monitoring the course of a known pathological process, the study of gamma glutamyl transpeptidase is literally irreplaceable in terms of clinical significance.
A significant increase in the activity of gamma glutamyl transpeptidase in myocardial infarction has not been detected, but it increases with pancreatic diseases and, in particular, diabetes mellitus. An increase in the activity of gamma glutamyl transpeptidase is also noted in infectious mononucleosis.