Re-elevation of gamma-glutamyl transpeptidase activity in periportal hepatocytes of rats with age.

Abstract

Changes in the level of gamma-glutamyl transpeptidase (gamma-GTP) in the rat liver with age were studied histochemically and biochemically. A high enzyme activity was seen throughout the hepatic lobule with some predominance in the periportal area in the neonatal rat liver. This enzyme activity disappeared almost completely from the hepatocytes of young adults. However, after 30 weeks of age, there was a gradual re-elevation of the enzyme activity in the periportal hepatocytes, attaining a level similar to that of neonatal liver. Expression of gamma-GTP activity in the rat hepatocytes is associated with not only onconeonatal events but also aging.