High sensitivity of Nrf2 knockout mice to acetaminophen hepatotoxicity associated with decreased expression of ARE-regulated drug metabolizing enzymes and antioxidant genes

Toxicol Sci. 2001 Jan;59(1):169-77. doi: 10.1093/toxsci/59.1.169.


Nrf2, which belongs to the basic leucine zipper (bZip) transcription factor family, has been implicated as a key molecule involved in antioxidant-responsive element (ARE)-mediated gene expression. In order to examine the role of Nrf2 in protection against xenobiotic toxicity, the sensitivity of nrf2 knockout mice to acetaminophen (N-acetyl-4-aminophenol (APAP)) was analyzed. The saturation of detoxification pathways after high levels of exposure to APAP is known to induce hepatotoxicity. Two factors important in its detoxification are UDP-glucuronosyltransferase (UDP-GT), an ARE-regulated phase-II drug-metabolizing enzyme, and glutathione (GSH), an antioxidant molecule whose synthesis depends on ARE-regulated gamma-glutamylcysteine synthetase (gammaGCS). Two- to 4-month-old male mice were orally administered a single dose of APAP at 0, 150, 300, or 600 mg/kg. Doses of 300 mg/kg APAP or greater caused death in the homozygous knockout mice only, and those that survived showed a greater severity in hepatic damage than the wild-type mice, as demonstrated by increased plasma alanine aminotransferase activity, decreased hepatic non-protein sulfhydryl (NPSH) content, and centrilobular hepatocellular necrosis. The high sensitivity of Nrf2-deficient mice was confirmed from observations made at 0, 2, 8, and 24 h after dosing with 300 mg/kg APAP; increased anti-APAP immunoreactivity was also noted in their livers at 2 h. Untreated homozygous knockout mice showed both a lower UDP-GT activity and NPSH content, which corresponded to decreased mRNA levels of UDP-GT (Ugt1a6) and the heavy chain of gammaGCS, respectively. These results show that Nrf2 plays a protective role against APAP hepatotoxicity by regulating both drug metabolizing enzymes and antioxidant genes through the ARE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetaminophen / administration & dosage
  • Acetaminophen / pharmacokinetics
  • Acetaminophen / toxicity*
  • Alanine Transaminase / blood
  • Animals
  • Chemical and Drug Induced Liver Injury / genetics
  • Chemical and Drug Induced Liver Injury / metabolism*
  • Chemical and Drug Induced Liver Injury / prevention & control
  • DNA-Binding Proteins / deficiency
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Dose-Response Relationship, Drug
  • Fluorescent Antibody Technique, Indirect
  • Gene Expression Regulation, Enzymologic*
  • Glucuronosyltransferase / genetics*
  • Glucuronosyltransferase / metabolism
  • Glutamate-Cysteine Ligase / genetics
  • Glutamate-Cysteine Ligase / metabolism
  • Glutathione / analysis
  • Glutathione / genetics*
  • Glutathione / metabolism
  • Heterozygote
  • Homozygote
  • Male
  • Mice
  • Mice, Inbred ICR
  • Mice, Knockout
  • Microsomes, Liver / drug effects
  • Microsomes, Liver / enzymology
  • NF-E2-Related Factor 2
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Trans-Activators / deficiency
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*


  • DNA-Binding Proteins
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, mouse
  • RNA, Messenger
  • Trans-Activators
  • Acetaminophen
  • Glucuronosyltransferase
  • Alanine Transaminase
  • Glutamate-Cysteine Ligase
  • Glutathione