Serum and liver glycylproline dipeptidyl aminopeptidase activity in rats with experimental hepatic cancer.

Changes of glycylproline dipeptidyl aminopeptidase (GPDA) and gamma-glutamyl transpeptidase (gamma-GTP) activities were compared in the serum and liver tissue of rats with hepatic cancer induced by 3'-methyl DAB. Serum glycylproline dipeptidyl aminopeptidase activity in rats with the azo dye-induced hepatic cancer was significantly higher than that in healthy rats, but the increase was not so extensive compared with that of gamma-glutamyl transpeptidase. The specific activity of glycylproline dipeptidyl aminopeptidase was decrease in the microsomal fraction and increased in the supernatant fraction of hepatic cancer tissue, whereas that of gamma-glutamyl transpeptidase was increased in both microsomal and supernatant fractions. These results suggest that the mechanisms, whereby serum activities of these two enzymes were increased in rats with hepatic cancer, were different from each other.

Electrophoretic fractionation of serum gamma-glutamyl transpeptidase in human hepatic cancer.

Serum gamma-glutamyl transpeptidase from patients with various hepatobiliary diseases was fractionated by polyacrylamide gradient gel slab electrophoresis to study the specific patterns of gamma-glutamyl transpeptidase fractions in hepatic cancer. On zymograms of normal serum gamma-glutamyl transpeptidase, a total of 10 fractions was observed. Additionally, fractions I', I" and II' were recognized in sera from hepatocellular carcinoma patients. Among these, fraction I', which migrated slightly, but significantly, slower than fraction I was the most specific; it was found in 55% of the hepatocellular carcinoma patients. Fractions I" and II' were also relatively specific, each was observed in about 29% of these patients. Fractions V to IX were observed in few hepatocellular carcinoma cases. Fraction I' is thought to be a hepatoma-related fraction, highly specific for the serum of hepatocellular carcinoma patients. Fractions I" and II' were also thought to be hepatoma-related fractions of gamma-glutamyl transpeptidase. We suggest that fractions I', I" and II' may be useful in the diagnosis of hepatocellular carcinoma.