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Target Organs and Levels of Evidence for TR-487

Toxicology and Carcinogenesis Studies of Isobutene (CASRN 115-11-7) in F344/N Rats and B6C3F1 Mice (Inhalation Studies)

Chemical (Study Title)
CASRN
Peer Review DatePrimary UsesRoute/Exposure LevelsStudy Laboratory
Isobutene
115-11-7
12/10/1997Production of diisobutylene, trimers, butyl rubber, antioxidants for foods, packaging, food supplements & plastics, isooctane, high-octane aviation gasoline. Polyisobutene resins. (NTP executive summary). Associated with tobacco: reported either as a natural component of tobacco, pyrolysis product (in tobacco smoke), or additive for one or more types of tobacco products.Inhalation
R&M: 0, 500, 2000, OR 8000 PPM (50/SEX/SPECIES/GROUP)
Battelle Northwest Laboratory

Levels of Evidence

Male Rats: Some Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Thyroid Gland Follicular Cell: CARCINOMA 1/48 0/48 0/48 5/50
Non-Neoplastic Lesions
  • NASAL CAVITY: SEVERITY OF OLFACTORY EPITHELIAL HYALINE DEGENERATION
Female Rats: No Evidence
TypeOrgan/Tissue (Lesion)
Non-Neoplastic Lesions
  • NASAL CAVITY: SEVERITY OF OLFACTORY EPITHELIAL HYALINE DEGENERATION
Male Mice: No Evidence
TypeOrgan/Tissue (Lesion)
Non-Neoplastic Lesions
  • NASAL CAVITY: EPITHELIAL HYALINE DEGENERATION
Female Mice: No Evidence
TypeOrgan/Tissue (Lesion)
Non-Neoplastic Lesions
  • NASAL CAVITY: EPITHELIAL HYALINE DEGENERATION