title: Cytogenic analysis of dominant lethal effects of mitomycin C and ethyl methanesulfonate.
abstract: To gain further insight into the mechanism of induction of dominant lethal mutations, the relationship between chromosome aberrations in bone marrow and in male germ cells after treatment with mitomycin C (MMC) and ethyl methanesulfonate (EMS) was examined. In addition, we obtained fertilized eggs from the oviducts of crossbred female mice in the same way as in the dominant lethal mutation test, and examined chromosome aberrations in male pronuclei. MMC 2.5 and 5.0 mg/kg, EMS 175 and 350 mg/kg were given subcutaneously to slc-ICR mice. It was concluded that MMC causes a decrease in the sperm count by killing germ cells, which in turn causes an increase in the number of unfertilized eggs and preimplantation egg loss. MMC seems also to cause invisible damages in the chromosomes of spermatocytes which lead to dominant lethality. EMS induced chromosome damage in the post-meiotic germ cells, and this damage, in turn, produced chromosome aberrations in the eggs, resulting in a high incidence of dominant lethality.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D002869:Chromosome Aberrations; D005020:Ethyl Methanesulfonate / Q000633:toxicity; D005260:Female; D005854:Germ Cells / Q000187:drug effects*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D016685:Mitomycin; D008937:Mitomycins / Q000633:toxicity; D009153:Mutagens / Q000633:toxicity*; D013090:Spermatocytes / Q000187:drug effects; D013093:Spermatogonia / Q000187:drug effects; D015053:Zygote / Q000187:drug effects
chemical_list: D008937:Mitomycins; D009153:Mutagens; D016685:Mitomycin; D005020:Ethyl Methanesulfonate