methylnitronitrosoguanidine has been researched along with benzidine* in 2 studies
2 other study(ies) available for methylnitronitrosoguanidine and benzidine
| Article | Year |
|---|---|
Strain differences in in vitro rat hepatocyte unscheduled DNA synthesis (UDS): effect of UV is independent of strain while increased sensitivity is apparent using Fischer-344 instead of Sprague-Dawley rats.
The unscheduled DNA synthesis (UDS) assay measures DNA repair following in vitro treatment of rat primary hepatocytes. This report compares the UDS response of primary hepatocytes from 2 widely used rat strains, the Fischer-344 (F344) and Sprague-Dawley (SD) strains. Ultraviolet (UV) light and 5 known genotoxic chemicals were evaluated in each strain in parallel experiments. The chemicals tested were 2-acetylaminofluorene (2-AAF), 4-aminobiphenyl (4-AB), benzidine, dimethylnitrosamine (DMN) and N-propyl-N'-nitro-N-nitrosoguanidine (PNNG). Four of these compounds (2-AAF, 4-AB, benzidine and DMN) require metabolic activation. Benzidine and PNNG were both negative using SD rat hepatocytes, but were weakly positive using F344 rat hepatocytes. In the first of 2 experiments, 4-AB was inconclusive in SD hepatocytes, but strongly positive in F344 cells. In the second experiment, 4-AB was positive in hepatocytes from both strains. 2-AAF was more strongly positive in F344 cells than in SD cells. DMN and UV light induced positive dose responses with little or no differences between strains. It is concluded that hepatocytes from F344 rats may be more sensitive, qualitatively and quantitatively, than hepatocytes from SD rats as indicators of UDS. This difference is not due to intrinsic differences in DNA repair mechanisms but is probably due to differences in drug-metabolizing enzymes between these strains. Thus, for routine screening, F344 rats are preferable for measurement of the in vitro UDS-inducing potential of compounds. Topics: 2-Acetylaminofluorene; Aminobiphenyl Compounds; Animals; Benzidines; Dimethylnitrosamine; DNA; DNA Repair; Liver; Male; Methylnitronitrosoguanidine; Mutagenicity Tests; Rats; Rats, Inbred F344; Rats, Inbred Strains; Species Specificity; Ultraviolet Rays | 1991 |
Dose-response studies on neoplastic transformation of BALB/3T3 clone A31-1-1 cells by aflatoxin B1, benzidine, benzo[a]pyrene, 3-methylcholanthrene, and N-methyl-N'-nitro-N-nitrosoguanidine.
The BALB/3T3 clone A31-1-1 mouse embryo cell line at passages 7 to 13 was selected for morphologic studies of neoplastic transformation by carcinogens of different chemical classes, in the absence of any added extracellular metabolic activation. Dose-related transforming activity was demonstrated for the carcinogens aflatoxin B1 (AFB) and benzidine (BZ) not previously reported in this system, and was confirmed for benzo[a]pyrene (BP), 3-methylcholanthrene (MCA), and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Spontaneous transformation per cells at risk was low (0.14 type III foci x 10(-4), while chemically induced transformation was 2 to 3 orders of magnitude higher with all compounds. The molar concentration of carcinogens in complete medium, required to induce a transformation frequency of 1.0 type III foci x 10(-3) showed the highest level of activity for BP (0.04 microns), an intermediate level for AFB (0.2 to 1.4 microns), MCA (1.1 micron), and MNNG (2.3 microns), and the lowest level of activity for BZ (30.0 microns). The dose-related induction of morphological transformation in this clone by carcinogens of different classes indicates the potential value of this biological system in quantitative studies of carcinogen combinations, especially at low dose levels. Topics: Aflatoxin B1; Aflatoxins; Animals; Benzidines; Benzo(a)pyrene; Benzopyrenes; Carcinogens; Cell Transformation, Neoplastic; Cells, Cultured; Clone Cells; Methylcholanthrene; Methylnitronitrosoguanidine; Mice; Mice, Inbred BALB C | 1983 |