Micronucleus induction in mouse and rat fetuses treated transplacentally during histogenesis with mitomycin C and 7,12-dimethylbenz(a)anthracene.
During histogenesis, mouse and rat fetuses were treated transplacentally with mitomycin C (MMC) and 7,12-dimethylbenz(a)anthracene (DMBA). The micronucleus (MN)-inducing effects of MMC were analysed in mouse fetal blood and liver; the effects of DMBA were analysed in mouse fetal and rat fetal blood and in maternal bone marrow of both species. Both test substances were clearly clastogenic during the period of development in which the embryos were analysed--i.e., MMC from gestational day 14 until day 18 in mice and DMBA on days 14 and 17 in mice and days 16 and 19 in rats. In mouse fetal liver and blood the MMC-induced MN frequencies did not vary significantly during the whole period. MMC was more effective in fetal blood than in fetal liver. DMBA-induced MN frequencies in maternal bone marrow were slightly higher in rats than in mice. Compared to maternal bone marrow, fetal MN frequencies were about four to five times higher in rats but less than two times higher in mice. Thus, rat fetuses were far more susceptible to the clastogenic action of DMBA than mouse fetuses. These results are discussed with respect to fetal development and maternal/fetal metabolism.
Müller
L
L
Institute for Drugs, Federal Health Office, Berlin, Federal Republic of Germany.
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D004900:Erythroblasts / Q000187:drug effects*; D005260:Female; D008431:Maternal-Fetal Exchange; D051379:Mice; D015162:Micronucleus Tests; D016685:Mitomycin; D008937:Mitomycins / Q000378:metabolism / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D008937:Mitomycins; D016685:Mitomycin; D015127:9,10-Dimethyl-1,2-benzanthracene