Nitrite-induced volatile mutagens from normal human feces

Abstract
Volatile mutagens (putative carcinogens) were produced from normal human and animal feces upon incubation with sodium nitrite in saline at 37.degree. C for 48 h. The mutagens were detected by using Ames'' Salmonella typhimurium tester strain TA1535 without microsomes, on plates inverted over samples in sealed containers. Mutagenicity was maximal at 0.2-0.6 M NaNO2 and at pH 6.2-6.8. Reversions per plate varied from .apprx. 30-450 (1.5-25 .times. background) within the normal human population. Sodium ascorbate and .alpha.-tocopherol (at 1/2 [NaNO2]) each reduced the mutagenicity by .apprx. 30%. Two standard N-nitroso-compounds were mutagenic in the system. The mutagenicity in this system is probably caused by the formation of volatile N-nitroso-compounds. Addition of nitrite to human feces in vitro enhances a process that occurs in vivo.