Chemically-induced sister-chromatid exchange in vivo in bone marrow of Chinese hamsters. An evaluation of 24 compounds.

Chemically-induced sister-chromatid exchange (SCE) was measured in vivo in bone marrow of Chinese hamsters. Chemicals were administered either intraperitoneally or orally and increased SCE frequencies were noted with 6 of 6 direct-acting genotoxins and with 9 of 14 activation-dependent genotoxins. Metronidazole, o-toluidine, 4-nitro-o-phenylenediamine and 2-nitro-p-phenylenediamine, compounds which have shown either mutagenic or carcinogenic activity, did not induce SCE in vivo, 4 non-genotoxins and 4 different control treatments did not induce SCE. The results show that the in vivo SCE method may be useful for the identification of genotoxins and that the outcome of the test is, for certain chemicals, dependent upon the route of exposure.