CHANGES IN THE ACTIVITIES OF GLUCOSE-6-PHOSPHATASE, ALDOLASE, AND ALKALINE PHOSPHATASE DURING AZO-DYE CARCINOGENESIS

Abstract

The activities of glucose-6-phosphatase, aldolase, and alkaline phosphatase were measured in rat liver during the early stage in the feeding of 3'-methyl-4-(dimethylamino) azobenzene. Enzyme activities changed quantitatively and qualitatively according to histological alteration in the cell population.
The fluctuation of enzyme activities occurred in three stages. The first stage was observed within 3 weeks after dye feeding. Activities of three enzymes decreased markedly, except for a slight increase in Mg²⁺-insensitive alkaline phosphatase at the second week. The second stage was seen between 4 and 8 weeks with a peak at the 6th week. Enzyme activities were elevated, and the muscle-type aldolase and Mg²⁺-insensitive alkaline phosphatase increased. In the third stage, after 8 weeks on, the altered patterns of these enzymes were maintained in hepatocyte fractions throughout the precancerous stage. It was suggested that the hepatocytes regenerated during 4-8 weeks acquire different characters from those of the origianl hepatocytes.