Deoxycytidylate deaminase and related enzymes of thymidine triphosphate metabolism in hepatomas and precancerous rat liver

摘要: Abstract Certain enzymes of thymidine triphosphate metabolism viz. deoxycytidylate deaminase, thymidylate synthetase, kinase and thymine catabolic activities were studied in livers from rats fed the hepatocarcinogen 3′-methyl-4-dimethylaminoazobenzene. Neither 0.06% nor 0.05% 3′-MDAB diet caused any significant increases dTMP synthetase over 17–19 weeks dye-feeding. Thymine activity was severely depressed for first three dye-feeding but by 4th week had returned to, thereafter remained at, high adult liver levels. Changes dCMP deaminase TdR during feeding closely paralleled each other. Both distinctly elevated after 2 on dye-diet. The these two several then reverted toward low levels 8 If present results are considered light prior studies (1) histological changes 3′-MDAB-fed rats, (2) biochemical characteristics α-naphylisothiocyanate, (3) alterations dTTP pathway certain “minimal deviation” hepatomas, (4) existence “fetal” “adult” types and, possibly, noted carcinogenesis might reflect shifts cell populations rather than altered regulation enzyme or synthesis. A theoretical model incorporating this concept is presented discussed with respect to metabolic diversity hepatomas.