gamma-Glutamyltransferase activity in atypical acinar cell nodules of rat pancreas.
The biochemical and histochemical measurement of the enzyme gamma-glutamyltransferase (GGT) was undertaken in normal rat pancreas and in rat pancreas containing azaserine-induced preneoplastic nodules. A steady decrease in pancreatic GGT activity was observed in the normal animals as they aged from 5 to 34 weeks. The azaserine-induced nodules contained a lower average GGT activity than the control pancreas although a 10-fold variation was noted in the GGT activity of individual nodules. A significant increase in concentrations of both reduced glutathione and oxidized glutathione was noted in pancreatic nodules from azaserine-treated rats compared to concentrations found in both control pancreas from untreated rats and internodular pancreas from azaserine-treated rats. A pancreatic acinar cell carcinoma contained low GGT activity--similar to that found in large nodules and about 10% of the level found in control pancreas. Pancreatic GGT levels were higher in 5- and 7-week-old rats fed chow than in rats fed a purified diet, but this effect of chow was not observed at 34 weeks of age. Feeding a purified diet supplemented with a retinoid, N-2-hydroxyethylretinamide (2-HER), for a period of 2 weeks did not influence the GGT activity level in either normal pancreas or in the azaserine-induced nodules. While decreased GGT activity does not serve as a marker for all atypical acinar cell nodules, deficient activity with concomitant increased glutathione levels appears to correlate generally with increased growth potential.
D000818:Animals; D001377:Azaserine / Q000633:toxicity; D004032:Diet; D005978:Glutathione / Q000032:analysis; D008297:Male; D010179:Pancreas / Q000201:enzymology*; D010190:Pancreatic Neoplasms / Q000201:enzymology*; D011230:Precancerous Conditions / Q000201:enzymology*; D051381:Rats; D011917:Rats, Inbred Lew; D005723:gamma-Glutamyltransferase / Q000032:analysis*
D001377:Azaserine; D005723:gamma-Glutamyltransferase; D005978:Glutathione