title: Hepatotumorigenicity of ethyl tertiary-butyl ether with 2-year inhalation exposure in F344 rats.
abstract: Carcinogenicity of ethyl tertiary-butyl ether (ETBE) was examined with inhalation exposure using F344/DuCrlCrlj rats. Groups of 50 male and 50 female rats, 6 week old at commencement, were exposed to ETBE at 0, 500, 1,500 or 5,000 ppm (v/v) in whole-body inhalation chambers for 6 h/day, 5 days/week for 104 weeks. A significant increase in the incidence of hepatocellular adenomas was indicated in males exposed at 5,000 ppm, but not in females at any concentration. In addition, significantly increased incidences of eosinophilic and basophilic cell foci were observed in male rats at 5,000 ppm. Regarding non-neoplastic lesions, rat-specific changes were observed in kidney, with an increase in the severity of chronic progressive nephropathy in both sexes at 5,000 ppm. Increased incidences of urothelial hyperplasia of the pelvis were observed at 1,500 ppm and above, and mineral deposition was apparent in the renal papilla at 5,000 ppm in males. There were no treatment-related histopathological changes observed in any other organs or tissues in either sex. The present 2-year inhalation study demonstrated hepatotumorigenicity of ETBE in male, but not in female rats.
authors: Japan Bioassay Research Center, Japan Industrial Safety and Health Association, 2445 Hirasawa, Hadano, 257-0015, Kanagawa, Japan. a-saito@jisha.or.jp
authors: Arata
authors: A
authors: Saito
authors: Toshiaki
authors: T
authors: Sasaki
authors: Tatuya
authors: T
authors: Kasai
authors: Taku
authors: T
authors: Katagiri
authors: Tomoshi
authors: T
authors: Nishizawa
authors: Tadashi
authors: T
authors: Noguchi
authors: Shigetoshi
authors: S
authors: Aiso
authors: Kasuke
authors: K
authors: Nagano
authors: Shoji
authors: S
authors: Fukushima
mesh_terms: D000236:Adenoma / Q000139:chemically induced* / Q000473:pathology; D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D015197:Carcinogenicity Tests; D002273:Carcinogens / Q000633:toxicity*; D002908:Chronic Disease; D005019:Ethyl Ethers / Q000633:toxicity*; D005260:Female; D019570:Inhalation Exposure; D007668:Kidney / Q000187:drug effects / Q000473:pathology; D007674:Kidney Diseases / Q000139:chemically induced / Q000473:pathology; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D012737:Sex Factors
chemical_list: D000393:Air Pollutants; D002273:Carcinogens; D005019:Ethyl Ethers; C098546:ethyl tert-butyl ether