THE DISTRIBUTION OF RIBONUCLEASE ACTIVITY IN RAT LIVER DURING AZO-DYE CARCINOGENESIS

Abstract

The distribution of ribonuclease activity in the liver of azo-dye fed animals was investigated histochemically using the substrate film method. The ribonuclease activity of liver parenchyma was lower than normal in cirrhotic and neoplastic rat livers while high activities were observed in the bile duct and connective tissue trabeculae. Intense reactions were also given by the necrotic regions. The decrease in ribonuclease activity of parenchymal cells was found to take place at early stages of 4-dimethylaminoazobenzene feeding, that is before hyperplastic cells are transformed into cancerous cells. No similar variation could be observed in the liver of animals fed the control basal diet nor in normal regenerating liver following partial hepatectomy.