title: Micronucleus test with methyl methanesulfonate administered by intraperitoneal injection and oral gavage.
abstract: The effects of 2 routes of administration, intraperitoneal injection (i.p.) and oral gavage (p.o.), in the micronucleus test were evaluated using methyl methanesulfonate (MMS) and 2 strains of mice (MS/Ae and CD-1). A small-scale acute toxicity study and a pilot micronucleus experiment were carried out first. On the basis of the results obtained, a final micronucleus test was performed at doses of 20, 40, 80, and 160 mg/kg (i.p.) and 40, 80, 160, and 320 mg/kg (p.o.), with a 24-h sampling time. MMS induced micronucleated polychromatic erythrocytes (MNPCEs) in both routes in both mouse strains under the conditions used. At 40 and 80 mg/kg, MMS induced a higher number of MNPCEs by the i.p. route in both strains. A 160 mg/kg MMS dose induced higher numbers of MNPCEs by the p.o. route in MS/Ae mice. The route-related difference with MMS on the basis of mg/kg disappeared when the difference was determined on the basis of a ratio of the LD50. In practice, both i.p. and p.o. routes are acceptable as routes of administration in the micronucleus test using this chemical.
authors.affiliation: Research Department, Sunstar Inc., Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tsuyoshi
authors.forename: M
authors.initials: M
authors.lastname: Takeuchi
authors.forename: H
authors.initials: H
authors.lastname: Hirono
authors.forename: Y
authors.initials: Y
authors.lastname: Masamoto
mesh_terms: D000284:Administration, Oral; D000818:Animals; D007274:Injections, Intraperitoneal; D007928:Lethal Dose 50; D008297:Male; D008741:Methyl Methanesulfonate / Q000008:administration & dosage* / Q000633:toxicity; D051379:Mice; D015162:Micronucleus Tests; D009153:Mutagens / Q000008:administration & dosage*; D010865:Pilot Projects
chemical_list: D009153:Mutagens; D008741:Methyl Methanesulfonate