Skip to main content
Log in

Mechanism of the protective action of n-acetylcysteine and methionine against paracetamol toxicity in the hamster

  • Original Investigations
  • Published:
Archives of Toxicology Aims and scope Submit manuscript

Abstract

The mechanism of the protective action of methionine and N-acetylcysteine against the toxicity of paracetamol was investigated in vivo. N-acetylcysteine inhibited the O-deethylation of ethoxyresorufin (cytochrome P-448) while methionine enhanced the N-demethylation of benzphetamine (cytochrome P-450) and increased hepatic microsomal levels of cytochrome P-450. These observations indicate that N-acetylcysteine, but not methionine, could afford protection against paracetamol hepatotoxicity, at least partly, by inhibiting cytochrome P-448 activity and thus the generation of the reactive intermediate. However, previous studies demonstrating no decrease in the urinary excretion of glutathione conjugates of paracetamol (derived from the reactive intermediate) in animals treated with N-acetylcysteine suggest that this is unlikely to be the prevailing mechanism of action.

Administration of a large dose of paracetamol, as expected, depleted glutathione levels and inhibited cytosolic glutathione transferase activity. Administration of either N-acetylcysteine or methionine 1 h after paracetamol prevented both effects. On the basis of the present work and previously published observations, it is concluded that the major mechanism of action of N-acetylcysteine and methionine in vivo is by acting as precursors of intracellular glutathione.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Akerboom TPM, Sies H (1981) Assay of glutathione, glutathione disulphide and glutathione mixed disulphides in biological samples. Methods Enzymol 77: 373–382

    Google Scholar 

  • Buckpitt AR, Rollins DE, Mitchell JR (1979) Varying effects of sulfhydryl nucleophiles on acetaminophen oxidation and sulfhydryl adduct formation. Biochem Pharmacol 83: 168–177

    Google Scholar 

  • Burke MD, Mayer RT (1974) Ethoxyresorufin: Direct fluorimetric assay of microsomal O-dealkylation which is preferentially inducible by 3-methylcholanthrene. Drug Metab Disp2: 583–588

    Google Scholar 

  • Campbell TC, Hayes JR, Newberne PM (1978) Dietary lipotropes, hepatic mixed-function oxidase activities and in vivo covalent binding of aflatoxin B1 in rats. Cancer Res 38: 4569–4573

    Google Scholar 

  • Carlberg I, Mannervik B (1975) Purification and characterisation of the flavoenzyme glutathione reductase from rat liver. J Biol Chem 250: 5475–5480

    Google Scholar 

  • Crome P, Volans GN, Vale JA, Widdop B, Goulding R, Williams RS (1976) The use of methionine for acute paracetamol poisoning. J Int Med Res 4: 105–111

    Google Scholar 

  • Dahlin DC, Miwa GT, Lu AYH, Nelson SD (1984) N-acetyl-p-benzoquinonone imine: A cytochrome P-450-mediated oxidation product of acetaminophen. Proc Natl Acad Sci USA 81: 1327–1331

    Google Scholar 

  • Davis DC, Potter WZ, Jollow DJ, Mitchell JR (1974) Species differences in hepatic glutathione depletion, covalent binding and hepatic necrosis after acetaminophen. Life Sci 14: 2099–2109

    Google Scholar 

  • Dawson JR, Norbeck K, Anundi I, Moldeus P (1984) The effectiveness of N-acetylcysteine in isolated hepatocytes against the toxicity of paracetamol, acrolein and paraquat. Arch Toxicol 55: 11–15

    Google Scholar 

  • Edes TE, Clinton SK, Truex CR, Visek WJ (1979) Intestinal and hepatic mixed-function oxidase activity in rats fed methionine and cysteine-free diets. Proc Soc Exp Biol Med 162: 71–74

    Google Scholar 

  • Gemborys MW, Mudge GH (1981) Formation and disposition of the minor metabolites of acetaminophen in the hamster. Drug Metab Disp 9: 340–351

    Google Scholar 

  • Golden DP, Mosby EL, Smith DJ, Mackercher P (1982) Acetaminophen toxicity: Report of two cases. Oral Med 51: 385–389

    Google Scholar 

  • Habig WH, Pabst MJ, Jakoby WB (1974) Glutathione-S-transferases. The first enzymatic step in mercapturic acid formation. J Biol Chem 249: 7130–7139

    Google Scholar 

  • Holme JA, Dahlin DC, Nelson SD, Dybing E (1984) Cytotoxic effects of N-acetyl-p-benzoquinone imine, a common arylating intermediate of paracetamol and N-hydroxy-paracetamol. Biochem Pharmacol 33: 401–406

    Google Scholar 

  • Ioannides C, Parke DV (1975) Mechanism of induction of hepatic drug metabolising enzymes by a series of barbiturates. J Pharm Pharmacol 27: 739–746

    Google Scholar 

  • Ioannides C, Steele CM, Parke DV (1983a) Species variation in the metabolic activation of paracetamol to toxic intermediates. Role of cytochromes P-450 and P-448. Toxicol Lett 16: 55–61

    Google Scholar 

  • Ioannides C, Hall DE, Mulder DE, Steele CM, Spickett J, Delaforge M, Parke DV (1983b)A comparison of the protective effects of N-acetylcysteine and S-carboxymethylcysteine against paracetamol-induced hepatotoxicity. Toxicology 28: 313–321

    Google Scholar 

  • Jollow DJ, Mitchell JR, Potter WZ, Davis DC, Gillette JR, Brodie BB (1973) Acetaminophen-induced hepatic necrosis. II. Role of covalent binding in vivo. J Pharmacol Exp Ther 187: 195–202

    Google Scholar 

  • Lauteburg BH, Corcoran GB, Mitchell JR (1982) N-Acetylcysteine protects against the hepatotoxicity of acetaminophen by reducing the reactive metabolite in rats in vivo. Gastroenterology 82: 1234

    Google Scholar 

  • Lin JH, Levy G (1981) Sulfate depletion after acetaminophen administration and replenishment by infusion of sodium sulfate or N-acetylcysteine in rats. Biochem Pharmacol 30: 2723–2725

    Google Scholar 

  • Lowry OH, Rosebrough NJ, Farr AL, Randall AJ (1951) Protein measurement with the Folin-phenol reagent. J Biol Chem 193: 265–275

    Google Scholar 

  • Lu AYH, Kuntzman R, West S, Jacobson M, Conney AH (1972) Reconstituted liver microsomal enzyme system that hydroxylates drugs, other foreign compounds and endogenous substrates. II. Role of the cytochrome P-450 and P-448 fractions in drug and steroid hydroxylations. J Biol Chem 247: 1727–1734

    Google Scholar 

  • Massey TE, Racz WJ (1981) Effects of N-acetylcysteine on metabolism, covalent binding, and toxicity of acetaminophen in isolated mouse hepatocytes. Toxicol Appl. Pharmacol 60: 220–228

    Google Scholar 

  • Meister A (1982) Metabolism and function of glutathione: an overview. Biochem Soc Trans 78: 78–79

    Google Scholar 

  • Meister A, Anderson ME (1983) Glutathione. Ann Rev Biochem 52: 711–760

    Google Scholar 

  • Miner DJ, Kissinger PT (1979) Evidence for the involvement of N-acetyl-p-quinone-imimine in acetaminophen metabolism. Biochem Pharmacol 28: 3285–3290

    Google Scholar 

  • Morgan ET, Koop DR, Coon MJ (1983) Comparison of six rabbit liver cytochrome P-450 isozymes in formation of a reactive metabolite of acetaminophen. Biochem Biophys Res Commun 112: 8–13

    Google Scholar 

  • Omura T, Sato R (1964) The carbon monoxide pigment of liver microsomes. I. Evidence for its haemoprotein nature. J Biol Chem 239: 2370–2378

    Google Scholar 

  • Phillipson CE, Godden PMM, Lum PY, Ioannides C, Parke DV (1984) Determination of cytochrome P-448 activity in biological tissues. Biochem J 221: 81–88

    Google Scholar 

  • Prescott LF, Park J, Sutherland GR, Smith IJ, Proudfoot AT (1976) Cysteamine, methionine and prenicillamine in the treatment of paracetamol poisoning. Lancet 2: 109–113

    Google Scholar 

  • Prescott LF, Ballantyne A, Park J, Adriaenssens P, Proudfoot AT (1977) Treatment of paracetamol (acetaminophen) poisoning with N-acetylcysteine. Lancet 2: 432–434

    Google Scholar 

  • Reed DJ, Orrenius S (1977) The role of methionine in glutathione biosynthesis by isolated hepatocytes. Biochem Biophys Res Commun 77: 1257–1264

    Google Scholar 

  • Steele CM, Masson HA, Battershill JM, Gibson GG, Ioannides C (1983) Metabolic activation of paracetamol by highly purified forms of cytochrome P-450. Res Commun Chem Pathol Pharmacol 40: 109–119

    Google Scholar 

  • Streeter AJ, Dahlin DC, Nelson SD, Baillie TA (1984) The covalent binding of acetaminophen to protein. Evidence for cysteine residues as major sites of arylation in vitro. Chem Biol Interact 48: 349–366

    Google Scholar 

  • Thor H, Moldeus P, Orrenius S (1979) Metabolic activation and hepatotoxicity. Effect of cysteine, N-acetylcysteine and methionine on glutathione biosynthesis and bromobenzene toxicity in isolated rat hepatocytes. Arch Biochem Biophys 192: 405–413

    Google Scholar 

  • Thorgeirsson SS, Sasame HA, Mitchell JR, Jollow DJ, Potter WZ (1976) Biochemical changes after hepatic injury from toxic doses of acetaminophen or furosemide. Pharmacology 14: 205–217

    Google Scholar 

  • Tredger JM, Smith HM, Davis M, Williams R (1980) Effects of sulphur-containing compounds on paracetamol activation and covalent binding in a mouse hepatic microsomal system. Toxicol Lett 5: 339–344

    Google Scholar 

  • Tredger JM, Smith HM, Davis M, Williams R (1981) In vitro interactions of sulfur-containing compounds with the hepatic mixed-function oxidase system in mice: Effects on paracetamol activation and covalent binding. Toxicol Appl Pharmacol 59: 111–124

    Google Scholar 

  • Vale JA, Meredith TJ, Crome P, Helliwell M, Volans GN, Widdop B, Goulding R (1979) Intravenous N-acetylcysteine: the treatment of choice in paracetamol poisoning? Br Med J 2: 1435–1436

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Pratt, S., Ioannides, C. Mechanism of the protective action of n-acetylcysteine and methionine against paracetamol toxicity in the hamster. Arch Toxicol 57, 173–177 (1985). https://doi.org/10.1007/BF00290883

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00290883

Key words

Navigation