National Toxicology Program

National Toxicology Program

Target Organs and Levels of Evidence for TR-406

Toxicology and Carcinogenesis Studies of g-Butyrolactone (CASRN 96-48-0) in F344/N Rats and B6C3F1 Mice (Gavage Studies)

Chemical (Study Title)
Peer Review DatePrimary UsesRoute/Exposure LevelsStudy Laboratory
07/09/1991Intermediate in the synthesis of polyvinylpyrrolidone, dl-methionine, piperidine, phenylbutyric acid, and thiobutyric acids. Solvent for resins. Constituent of paint removers. Textile aids. Drilling oils. 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.Gavage
MR: 0, 112, OR 225 MG/KG FR: 0, 225, OR 450 MG/KG M: 0, 262, OR 525 MG/KG; 50/SEX/SPECIES
Southern Research Institute

Levels of Evidence

Male Rats: No Evidence
Female Rats: No Evidence
TypeOrgan/Tissue (Lesion)
Other Considerations
  • MAMMARY GLAND: CYST 42/50 35/50 23/50; FIBROADENOMA 22/50 14/50 6/50
  • PITUITARY GLAND: CYST 25/49 13/37 11/48
Male Mice: Equivocal Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Adrenal Gland Medulla: PHEOCHROMOCYTOMA 1/48 5/50 1/50 OR MALIGNANT PHEOCHROMOCYTOMA 1/48 1/50 0/50 COMBINED 2/48 6/50 1/50
Non-Neoplastic Lesions
Other Considerations
  • LIVER: ADENOMA 8/50 6/50 1/50 OR CARCINOMA 16/50 2/50 8/50 COMBINED 24/50 8/50 9/50
Female Mice: No Evidence

NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.