Induction of unscheduled DNA synthesis by chemical mutagens in testicular cells of the mouse in vitro.

Testicular cells of male mice were isolated, and the incorporation of tritium labeled thymidine into the DNA of the cells was estimated after exposure to various chemical mutagens. The normal semiconservative DNA synthesis was suppressed by the addition of hydroxyurea. Thirteen compounds were tested. Unscheduled DNA synthesis (UDS) was stimulated by ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and triaziquone, and, to a lesser extent, by 4-nitroquinoline 1-oxide (4-NQO), mitomycin C, ICR-191 and nitrogen mustard (HN-2). No thymidine incorporation could be estimated after incubation of the cells with 9-aminoacridine, hydroxyurethane, alpha-naphthylamine, 2-acetylaminofluorene (AAF) nor with N-hydroxy-2-acetylaminofluorene (N-OH-AAF).