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https://ntp.niehs.nih.gov/go/LOE-TR-571

Kava kava extract: Target Organs and Levels of Evidence for TR-571

Toxicology and Carcinogenesis Studies of Kava Kava Extract (CASRN 9000-38-8) in F344/N Rats and B6C3F1 Mice (Gavage Studies)

Chemical (Study Title)
CASRN
Peer Review DateRoute/Exposure LevelsStudy Laboratory
Kava kava extract
9000-38-8
01/26/2011Gavage
R: 0, 0.1, 0.3, OR 1.0 G/KG; M: 0, 0.25, 0.5, OR 1.0 G/KG; 50/SEX/SPECIES/DOSE
Battelle Columbus Laboratory

Levels of Evidence

Male Rats: Equivocal Evidence
TypeOrgan/Tissue (Lesion)
May Have Been Related
  • Testis: Interstitial cell adenoma 37/49 44/50 49/50 46/50
Non-Neoplastic Lesions
  • Liver: Hepatocyte, hypertrophy; centrilobular, fatty change
  • Stomach, Forestomach: inflammation; ulcer; epithelium, hyperplasia
  • Kidney: Severity of nephropathy; pelvis, transitional epithelium, hyperplasia
  • Eye: Retina, degeneration
  • Pancreas: Acinus, metaplasia, hepatocyte
Female Rats: No Evidence
TypeOrgan/Tissue (Lesion)
Non-Neoplastic Lesions
  • Liver: Hepatocyte, hypertrophy
  • Stomach, Forestomach: inflammation; ulcer; epithelium, hyperplasia
  • Kidney: Nephropathy
  • Eye: Retina, degeneration
  • Pancreas: Acinus, metaplasia, hepatocyte
Male Mice: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Liver: Hepatoblastoma 0/50 4/50 9/50 12/50
Non-Neoplastic Lesions
  • Liver: Centrilobular, hypertrophy; eosinophilic focus; angiectasis; necrosis
Female Mice: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Liver: Hepatocellular carcinoma 3/50 13/50 8/50 8/50 hepatocellular adenoma or carcinoma 10/50 21/50 20/50 13/50
Non-Neoplastic Lesions
  • Liver: Centrilobular, hypertrophy; eosinophilic focus
  • Stomach, Forestomach: Inflammation, chronic; epithelium, hyperplasia; erosion; ulcer