Effect of Dietary 2-Acetylaminofluorene on Rat Liver Enzymes Involved in the Anabolism and Catabolism of Nucleic Acid Precursors

Abstract

The activities of the following enzymes have been determined in the soluble fraction of liver from rats fed a special basal diet supplemented with the carcinogen 2-acetylaminof luorene for various lengths of time: aspartate carbamoyltransferase, deoxycytidylate deaminase, deoxythymidylate kinase, the kinases which phosphorylate deoxycytidine, deoxythymidine, deoxyadenosine, and uridine, the phosphohydrolases which dephosphorylate the 5′-monophosphates of deoxythymidine, deoxyuridine, deoxycytidine, uridine and cytidine, and acid and alkaline non-specific phosphatases. Histological studies of the livers have also been performed. The enzyme activities showed widely different variation patterns during acetylamino-fluorene feeding. The deoxyadenosine and uridine kinase activities were not affected by the carcinogen, whereas all the other anabolic enzymes tested increased in activity within the experimental period. Also, the dephosphorylation of the nucleotides and the activity level of the acid phosphatase were increased. The alkaline phosphatase showed reduced activity. The results indicate that the enzymes were under specific influence of the carcinogen. The specificity of some of the enzymes has been discussed in relation to the observed activity variations.

Key Words:

• Acetylaminofluorene
• aspartate carbamoyltransferase
• carcinogenesis
• deoxycytidylate deaminase
• deoxythymidylate kinase
• nucleoside kinases
• 5′-nucleotidase
• phosphatase
• rat liver