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https://ntp.niehs.nih.gov/go/6418

Target Organs and Levels of Evidence for TR-516

Toxicology and Carcinogenesis Studies of 2-Methylimidazole (CASRN 693-98-1) in F344/N Rats and B6C3F1 Mice (Feed Studies)

Chemical (Study Title)
CASRN		 Peer Review Date Route/Exposure Levels Study Laboratory
2-Methylimidazole
693-98-1		 05/22/2003 Dosed-Feed
MR: 0, 300, 1000, OR 3000 PPM; FR: 0, 1000, 2500, OR 5000 PPM; M: 0, 625, 1250, OR 2500 PPM; 60/SEX/SPECIES/GROUP		 Southern Research Institute

Levels of Evidence

Male Rats: Some Evidence
Type Organ/Tissue (Lesion)
Neoplastic Lesions
  • Thyroid Gland Follicular Cell: ADENOMA OR CARCINOMA 1/48 2/46 1/43 5/50
May Have Been Related
  • Liver: ADENOMA OR CARCINOMA 0/50 1/50 3/50 3/50
Non-Neoplastic Lesions
  • THYROID GLAND: FOLLICULAR CELL HYPERPLASIA
  • LIVER: MIXED CELL FOCUS
Female Rats: Clear Evidence
Type Organ/Tissue (Lesion)
Neoplastic Lesions
  • Thyroid Gland Follicular Cell: ADENOMA 0/49 0/48 0/42 5/48 CARCINOMA 1/49 1/48 1/42 7/48 COMBINED 1/49 1/48 1/42 11/48
May Have Been Related
  • Liver: ADENOMA 1/50 0/49 2/50 4/50
Non-Neoplastic Lesions
  • THYROID GLAND: FOLLICULAR CELL HYPERPLASIA; MINERALIZATION
  • LIVER: BILE DUCT HYPERPLASIA; GRANULOMATOUS INFLAMMATION; MIXED CELL FOCUS
  • SPLEEN: GRANULOMATOUS INFLAMMATION
Male Mice: Some Evidence
Type Organ/Tissue (Lesion)
Neoplastic Lesions
  • Thyroid Gland Follicular Cell: ADENOMA 0/50 1/50 0/50 7/50
  • Liver: ADENOMA 7/50 14/50 13/50 18/50 CARCINOMA 4/50 8/50 14/50 6/50 COMBINED 10/50 22/50 22/50 22/50
Non-Neoplastic Lesions
  • THYROID GLAND: FOLLICULAR CELL HYPERPLASIA; FOLLICULAR CELL HYPERTROPHY
  • LIVER: HEPATOCYTE CYTOPLASMIC ALTERATION; HEPATOCYTE KARYOMEGALY; KUPFFER CELL PIGMENTATION
  • SPLEEN: HEMATOPOIETIC CELL PROLIFERATION; PIGMENTATION; LYMPHOID FOLLICLE ATROPHY
  • BONE MARROW: HYPERPLASIA
  • KIDNEY: PIGMENTATION
  • EPIDIDYMIS: CHRONIC ACTIVE INFLAMMATION; SPERM GRANULOMA
  • TESTES: GERMINAL EPITHELIAL ATROPHY
Female Mice: Some Evidence
Type Organ/Tissue (Lesion)
Neoplastic Lesions
  • Liver: ADENOMA 3/50 4/49 6/49 10/50
Non-Neoplastic Lesions
  • THYROID GLAND: FOLLICULAR CELL HYPERPLASIA; FOLLICULAR CELL HYPERTROPHY
  • SPLEEN: HEMATOPOIETIC CELL PROLIFERATION; PIGMENTATION