Mutagenicity studies with o-tolidine and 4,4'-tetramethyldiaminodiphenylmethane.

This paper confirms the mutagenicity of 2 carcinogenic chemicals, o-tolidine and 4,4'-tetramethyldiaminodiphenylmethane (TDDM). o-Tolidine and TDDM were both tested in the Salmonella/mammalian-microsome test and in the sister-chromatid exchange (SCE) test with rabbit lymphocytes in vitro. The number of revertants was increased in the presence of S9 mix by o-tolidine in the Salmonella typhimurium strains TA98 and TA1538, and by TDDM in strains TA98 and TA100. Both compounds showed weak SCE-inducing activity in cultured rabbit lymphocytes in the absence, but not in the presence, of an exogenous metabolic system.