A comparison of the mutagenicity and macromolecular binding of the carcinogens Michler's ketone and reduced Michler's ketone.

The mutagenicity of 4,4'-bis(dimethylamino)benzophenone (Michler's ketone, MK, CAS No. 90-94-8) and 4,4'-methylenebis(N,N-dimethyl)benzamine (reduced Michler's ketone, RMK, CAS No. 101-61-1) for Salmonella typhimurium strain TA100 was compared using activated 9000 X g (S9) liver supernatants from 2 animal species. RMK, but not MK, was mutagenic when incubated with phenobarbital-induced B6D2F1 mouse or Osborne-Mendel rat-liver S9. The mutagenic response for RMK was linear at doses from 1 to 33 micrograms/plate. A higher percentage of RMK and MK became irreversibly bound to mouse-liver macromolecules than to rat-liver macromolecules when incubated at 37 degrees C in the presence of reduced nicotinamide adenine dinucleotide phosphate.