RESUMO
Antimutagenic effect of p-aminobenzoic acid (PABA) and sodium bisulfite (NaHSO_3)on the mutagenicity of N-methyl-N-nitro-N-nitrosoguanidine (MNNG) was detected by the mehod of human lymphocytes unscheduled DNA Sythesis (LIDS). The results showed that when the concentration of PABA and NaHSO_3 was varied in presence of a constant concentration of MNNG, 5 ?10~(-5) mol/L concentration of PABA, 3 ? 10~(-4) mol/L concentration of NaHSO_3 were the most effective, while the concentration of MNNG varied in the presence of a constant concentration of PABA and NaHSO_3, antimutagenicity was the most effective at high concentration of MNNG. The results indicated that the PABA and NaHSO_3 exhibited antimutagenic activity towards MNNG-induced mutagenicity in LIDS and the extents of antimutagenicity were related with the concentration of MNNG.