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HGPRT point mutation assay
133 18 V/)lkner, W., E.W. Mi~ller and H.G. Miltenburger, Institut fi~r Zoologie, Technische Hochschule Darmstadt, D-6100 Darmstadt (F.R.G.)
Comparative investigations for the standardization of the mammalian spot test with different mice strains Most investigations use matings T x C57B1 or T x HT in the spot test. Other mouse strains are, however, also suitable (Russell et al., Mutation Res., 86 (1981) 355). We performed experiments to compare the suitability of the matings T x C57B1/6J and DBA x NMRI. Therefore, C57B1/6J females were crossed with males of different strains: -C57Br; NMRI; A / J ; DBA and T-stock which possess one or more recessive genes in the homozygous condition. The effect of ENU treatment was tested on days 7, 8, 9 and 10 of gravidity. The highest effect was found on day 8 or 9. The study yielded the following results: (1) The crossing DBA (males) × NMRI (females) yields higher litter sizes than C57B1/6J x T. (2) The post-natal mortality is much less. (3) Only 50 gravid mice are required for one experimental group to obtain reproducibly 300 F1 animals which can be scored for spots 3-4 weeks after birth. (4) A new standard protocol for the spot test using DBA/2J × NMRI could be established according to these findings.
19 Manolache, M., J. Gebauer and G. R6hrborn, Institute of Human Genetics, University Diisseldorf, Di~sseldorf (F.R.G.)
Mutagenic activity of aristolochic acid in the V 7 9 / H G P R T point mutation assay Aristolochic acid (AA), a pharmacologically active agent of the plant Aristolochia clematitis proved to be a potent mutagen/carcinogen in vivo and in vitro. Because of the results from several experimental studies during the last years the Federal Health Office withdrew the licence for drugs containing AA. To test the mutagenic activity of AA at the HGPRT locus, we treated V79 Chinese hamster cells with AA in concentrations ranging from 25 to 500 #g/ml culture medium; until now there have been no studies on the activity of AA in the V79/HGPRT point mutation assay. After 3-h treatment with AA (with and without $9 mix), V79 cultures were analyzed for survivors and 8-azaguanine-resistant cell clones (HGPRT-). At concentrations of 25-500/~g AA/ml we could not observe any significant cytotoxic effect. Nevertheless, the mutagenic activity of AA is clear-cut with and without $9 mix. In particular the high number of 8-azaguanine-resistant colonies shows AA to be a very potent mutagen.
20 Puri, E.C., and D. Miiller, Ciba-Geigy Ltd., CH-4002 Basle (Switzerland)
Mutagenic properties and carcinogenicity of aristolochic acid A few years ago, aristolochic acid (AA) was discovered to be carcinogenic (Mengs, U. et al., Arch. Toxicol., 51 (1982) 107-119). When examined in the Ames test, it proved to be mutagenic (Robisch, G. et al., Mutation Res., 105 (1982) 201-204). AA induces point mutations and recombinations in Drosophila melanogaster (Frei, H. et al., Experientia, 39 (1983) 685-686), and causes gaps, breaks, and an increase in the SCE rate in human lymphocytes in vitro (Abel, G., and O. Schimmer, Hum. Genet., 64 (1983) 131-133) and point mutations in V79 cells (Manolache, M. et al., (1984) abstract, this meeting).
Comparative investigations for the standardization of the mammalian spot test with different mice strains Most investigations use matings T x C57B1 or T x HT in the spot test. Other mouse strains are, however, also suitable (Russell et al., Mutation Res., 86 (1981) 355). We performed experiments to compare the suitability of the matings T x C57B1/6J and DBA x NMRI. Therefore, C57B1/6J females were crossed with males of different strains: -C57Br; NMRI; A / J ; DBA and T-stock which possess one or more recessive genes in the homozygous condition. The effect of ENU treatment was tested on days 7, 8, 9 and 10 of gravidity. The highest effect was found on day 8 or 9. The study yielded the following results: (1) The crossing DBA (males) × NMRI (females) yields higher litter sizes than C57B1/6J x T. (2) The post-natal mortality is much less. (3) Only 50 gravid mice are required for one experimental group to obtain reproducibly 300 F1 animals which can be scored for spots 3-4 weeks after birth. (4) A new standard protocol for the spot test using DBA/2J × NMRI could be established according to these findings.
19 Manolache, M., J. Gebauer and G. R6hrborn, Institute of Human Genetics, University Diisseldorf, Di~sseldorf (F.R.G.)
Mutagenic activity of aristolochic acid in the V 7 9 / H G P R T point mutation assay Aristolochic acid (AA), a pharmacologically active agent of the plant Aristolochia clematitis proved to be a potent mutagen/carcinogen in vivo and in vitro. Because of the results from several experimental studies during the last years the Federal Health Office withdrew the licence for drugs containing AA. To test the mutagenic activity of AA at the HGPRT locus, we treated V79 Chinese hamster cells with AA in concentrations ranging from 25 to 500 #g/ml culture medium; until now there have been no studies on the activity of AA in the V79/HGPRT point mutation assay. After 3-h treatment with AA (with and without $9 mix), V79 cultures were analyzed for survivors and 8-azaguanine-resistant cell clones (HGPRT-). At concentrations of 25-500/~g AA/ml we could not observe any significant cytotoxic effect. Nevertheless, the mutagenic activity of AA is clear-cut with and without $9 mix. In particular the high number of 8-azaguanine-resistant colonies shows AA to be a very potent mutagen.
20 Puri, E.C., and D. Miiller, Ciba-Geigy Ltd., CH-4002 Basle (Switzerland)
Mutagenic properties and carcinogenicity of aristolochic acid A few years ago, aristolochic acid (AA) was discovered to be carcinogenic (Mengs, U. et al., Arch. Toxicol., 51 (1982) 107-119). When examined in the Ames test, it proved to be mutagenic (Robisch, G. et al., Mutation Res., 105 (1982) 201-204). AA induces point mutations and recombinations in Drosophila melanogaster (Frei, H. et al., Experientia, 39 (1983) 685-686), and causes gaps, breaks, and an increase in the SCE rate in human lymphocytes in vitro (Abel, G., and O. Schimmer, Hum. Genet., 64 (1983) 131-133) and point mutations in V79 cells (Manolache, M. et al., (1984) abstract, this meeting).