The levels of seven enzymes involved in the metabolism of 1-carbon compounds and their precursors were investigated in the cytoplasmic fractions of the livers of rats receiving the hepatocarcinogens diethylnitrosamine, 2-acetylaminofluorene, and 7V,./V-dimethyl-4-aminoazobenzene for 1 to 5 weeks. The enzymes studied included serine hydroxymethylase, dihydrofolate reducÃ-ase (H2-folate reducÃ-as...
