title: Lack of micronucleus induction activity of ethyl tertiary-butyl ether in the bone marrow of F344 rats by sub-chronic drinking-water treatment, inhalation exposure, or acute intraperitoneal injection.
abstract: Ethyl tertiary-butyl ether (ETBE) is an oxygenated gasoline additive synthesized from ethanol and isobutene that is used to reduce CO2 emissions. To support the Kyoto Protocol, the production of ETBE has undergone a marked increase. Previous reports have indicated that exposure to ETBE or methyl tertiary-butyl ether resulted in liver and kidney tumors in rats and/or mice. These reports raise concern about the effects of human exposure being brought about by the increased use of ETBE. The present study was conducted to evaluate the genotoxicity of ETBE using micronucleus induction of polychromatic erythrocytes in the bone marrow of male and female rats treated with ETBE in the drinking-water at concentrations of 0, 1,600, 4,000 or 10,000 ppm or exposed to ETBE vapor at 0, 500, 1,500 or 5,000 ppm for 13 weeks. There were no significant increases in micronucleus induction in either the drinking water-administered or inhalation-administered groups at any concentration of ETBE; although, in both groups red blood cells and hemoglobin concentration were slightly reduced in the peripheral blood in rats administered the highest concentration of ETBE. In addition, two consecutive daily intraperitoneal injections of ETBE at doses of 0, 250, 500 or 1,000 mg/kg did not increase the frequency of micronucleated bone marrow cells in either sex; all rats receiving intraperitoneal injections of ETBE at a dose of 2,000 mg/kg died after treatment day 1. These data suggest that ETBE is not genotoxic in vivo.
authors.affiliation: Japan Bioassay Research Center, Japan Industrial Safety and Health Association.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Noguchi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kamigaito
authors.forename: Taku
authors.initials: T
authors.lastname: Katagiri
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kondou
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Aiso
authors.forename: Tomoshi
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Kasuke
authors.initials: K
authors.lastname: Nagano
authors.forename: Shoji
authors.initials: S
authors.lastname: Fukushima
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001853:Bone Marrow; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D060766:Drinking Water; D005019:Ethyl Ethers / Q000008:administration & dosage* / Q000633:toxicity*; D005260:Female; D005742:Gasoline; D019570:Inhalation Exposure; D007274:Injections, Intraperitoneal; D008297:Male; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects*; D015162:Micronucleus Tests; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D060766:Drinking Water; D005019:Ethyl Ethers; D005742:Gasoline; C098546:ethyl tert-butyl ether