National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/8510

Target Organs and Levels of Evidence for TR-486

Toxicology and Carcinogenesis Studies of Isoprene (CASRN 78-79-5) in F344/N Rats (Inhalation Studies)

Chemical (Study Title)
CASRN
Peer Review DatePrimary UsesRoute/Exposure LevelsStudy Laboratory
Isoprene
78-79-5
12/10/1997Monomer and comonomer for elastomers, prepared from turpentine, petroleum products (Merck 1989). 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: 0, 220, 700, OR 7000 PPM; 50/SEX/GROUP
Battelle Northwest Laboratory

Levels of Evidence

Male Rats: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Mammary Gland: FIBROADENOMA 2/50 4/50 6/50 21/50 FIBROADENOMA OR CARCINOMA COMBINED 2/50 5/50 7/50 21/50
  • Kidney Tubular Cell: (SINGLE SECTION) ADENOMA 0/50 2/50 2/50 6/50 (SINGLE AND STEP SECTION) ADENOMA 2/50 4/50 8/50 15/50
  • Testis: ADENOMA 33/50 37/50 44/50 48/50
Non-Neoplastic Lesions
  • KIDNEY: HYPERPLASIA
Female Rats: Some Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Mammary Gland: FIBROADENOMA 19/50 35/50 32/50 32/50 MULTIPLE FIBROADENOMA 7/50 12/50 19/50 17/50
May Have Been Related
  • Brain: ASTROCYTOMA 0/50 0/50 1/50 0/50, GLIOMA 0/50 0/50 0/50 1/50, MEDULOBLASTOMA 0/50 0/50 0/50 1/50, MENINGEAL GRANULAR CELL TUMOR 0/50 1/50 0/50 1/50, MENINGEAL SARCOMA 0/50 1/50 0/50 1/50


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