Cytogenetic effect of ortho-phenylenediamine in the mouse, Chinese hamster, and guinea pig and of derivatives, evaluated by the micronucleus test.

The mutagenic potential of ortho-phenylenediamine--known by studies on Salmonella typhimurium--was studied in mice, Chinese hamsters and Guinea pigs with the use of the micronucleus test. In bone marrow of all three species, chromosomal damage was detected following intraperitoneal injections of the test chemical, this damage was seen also after peroral administration to mice. Four derivatives of ortho-phenylenediamine containing one or two methyl-, nitro- or chlorosubstituents in 4- or 5-position of the aromatic ring were studied in mice. Of these the 4-methyl-derivative induced micronuclei, the 4-nitro-, 4,5-dimethyl-, and 4,5-dichloroderivatives were inactive. The results indicate that the chemical nature and the number of substituents influence the chromosome damaging potential.