Membrane enzyme cytochemical changes in the hepatocytes of diethylnitrosamine induced hepatomas

Male Wistar rats were treated by 9 i.p. injections with 100 mg/kg body weight diethylnitrosamine (DEN), in 9 consecutive weeks. After decapitation, between the 130th and 140th day, primary hepatocellular carcinomas were found. Tissue from 3 different parts of the liver was processed to study the activity of Glucose-6-Phosphatase in the membranes of the endoplasmic reticulum, Adenosinetriphosphatase in the cell (plasma) membrane and of Succinic-Dehydrogenase in mitochondrial membranes. In the experimental animals liver tissue revealed no activity of G-6-P in any region affected by the tumor. ATP and SDG activity was dependent on the type of lesion. Generally speaking it diminished with the lesser differentiation of the hepatoma cells. Other morphological and metabolic aspects of liver DEN cancerogenesis are discussed.