CHANGE IN ACID PHOSPHATASE DURING AZO-DYE CARCINOGENESIS

Abstract

The acid phosphatase activity in rat liver during the early stage in the feeding of 3'-methyl-4-(dimethylamino)azobenzene was examined with the liver homogenate, soluble fractions, fractions separated by column chromatography, and hepatocyte suspensions, using β-glycerophosphate and phenyl phosphate as substrates. The isozyme pattern of acid phosphatase was also studied by electrophoresis on cellulose acetate membrane.
The alteration in acid phosphatase activity showed three phases. The first phase occurred after 1-3 weeks of dye feeding, in which the enzyme activity decreased markedly, The second phase was observed during 4-8 weeks and showed recovery of the activity with a peak in the 6th week. The isozyme pattern of acid phosphatase in the liver and also in the hepatocyte fraction changed in this stage. The third phase appeared after 9 weeks. Through these phases, the ratio of activity with phenyl phosphate to that with β-glycerophosphate was higher than the normal value.
These changes seem to result from alterations of cell population and character of hepatocytes in liver by ingestion of the carcinogen.