On the mutagenicity of metabolites derived from the mushroom poison gyromitrin.

The hepatotoxic and carcinogenic hydrazine N-methyl-N-formyl hydrazine (MFH), which is formed from the mushroom poison gyromitrin by hydrolytic cleavage in vivo and in vitro during food processing is much more mutagenic for the strain TA 100 of Salmonella typhimurium in the presence of a metabolic activation system than in its absence. On the other hand, acetylated MFH (Ac-MFH) was not mutagenic for TA 100 in both test conditions. For the strain TA 98 neither MFH nor Ac-MFH were mutagenic both with and without metabolic activation. Therefore, a metabolic conversion of the free NH2-moiety of MFH into a genotoxic metabolite of MFH is postulated.