Glutathione deficiency in alcoholics: risk factor for paracetamol hepatotoxicity (original) (raw)
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The effects of ethanol on paracetamol-induced oxidative stress in mice liver
Journal of the Serbian Chemical Society, 2013
The aim of our study was to investigate the effects of binge drinking on paracetamol induced oxidative stress in mice liver. Male Swiss mice were divided into groups: control; ethanol-treated group (E) in five subsequent doses of 2 g/kg by orogastric tube; paracetamol-treated group (P) in a dose of 300 mg/kg intraperitoneally; group that received paracetamol 12 hrs after the last dose of ethanol (PE). Blood and liver samples were collected for determination of oxidative stress parameters 6, 24 and 48 hrs after treatment. Prior binge drinking potentiated paracetamol-induced rise in liver malondialdehyde level 48 hours after treatment in comparison with P and E groups (17.14 ? 1.98 vs 13.14 ? 0.82 and 12.99 ? 1.18 ?mol/L, p<0.01). Ethanol and paracetamol in combination induced a more pronounced decrease in liver GSH level than either of these substances alone at all time intervals (p<0.01). Total liver superoxide dismutase (SOD) activity was significantly lower in PE 48 hours af...
Enhancement by glutathione depletion of ethanol-induced acute hepatotoxicity in vitro and in vivo
Toxicology, 1987
Ethanol at initial concentrations between 0.75 and 6 g/1 produced a dosedependent release of the enzymes glutamic-pyruvic-transaminase and sorbitol dehydrogenase (GPT, SDH) from the isolated perfused rat liver. At the concentration of 6 g/l, it also decreased the oxygen consumption and elevated the calcium content of the isolated livers. These toxic effects of ethanol were significantly enhanced in livers, the glutathione content of which had been depleted by pretreatment with phorone. Ethanol-induced toxicity in glutathione-depleted isolated livers could be prevented both by inhibition of alcohol dehydrogenase with 4-methylpyrazole and of xanthine oxidase with allopurinol. In rats, in vivo, 1.6 g/kg ethanol injected intravenously produced a small increase in serum GPT and SDH concentrations 4 h after its administration. This increase in enzyme activities was severalfold higher and longer lasting in rats pretreated with phorone. Glutathione depletion per se did not induce hepatotoxicity in vitro or in vivo.
Effect of ethanol on glutathione concentration in isolated hepatocytes
The Biochemical journal, 1980
1. Ethanol induces a decrease in GSH (reduced glutathione) concentration is isolated hepatocytes. Maximal effects appear at 20 mM-ethanol. The concentration-dependence of this decrease is paralleled by the concentration-dependence of the activity of alcohol dehydrogenase. 2. Pyrazole, a specific inhibitor of alcohol dehydrogenase, prevents the ethanol-induced GSH depletion. 3. Acetaldehyde, above 0.05 mM, also promotes a decrease in GSH concentration in hepatocytes. 4. Disulfiram (0.05 mM), an inhibitor of aldehyde dehydrogenase, potentiates the fall in GSH concentration caused by acetaldehyde. 5. The findings support the hypothesis that acetaldehyde is responsible for the depletion of GSH induced by ethanol. 6. Methionine prevents the effect of alcohol or acetaldehyde on GSH concentration in hepatocytes.
Influence of acute ethanol administration on hepatic glutathione metabolism in the rat
Alcohol, 1988
The effect of acute ethanol administration on the hepatic metabolism of glutathione was studied in male Wistar rats. Animals fasted for 18 hr received ethanol (5 g/kg body wt.) through a gastric tube as a 20% (w/v) solution in 0.154 NaCl. Four hours after administration of ethanol liver glutathione content was decreased by 21% when compared to saline-treated controls. A significant reduction (28%) was also found in gamma-glutamylcysteine synthetase activity and plasma glutathione levels were increased non significantly by 17% with respect to control rats. Glutathione S-transferase activity in the liver of ethanol-treated animals was decreased by 28% but no change was found in total glutathione peroxidase activity. The results indicate that the lowered glutathione synthesis could be an important factor contributing to the reduction of hepatic glutathione concentration following the acute ingestion of ethanol.
Toxicology Letters, 1992
Since plasma reduced glutathione (GSH) seems to reflect liver GSH content, we have assessed plasma GSH in patients using paracetamol daily. In these patients a significant lower plasma GSH concentration was found with respect to controls. After the i.v. administration of GSH free plasma cysteine was 12 fold higher than in basal condition and all the pattern of plasma thiol groups was modified. This work suggests that the possible protective effect of GSH administration is due to the availability of plasma thiol compounds that enter the cell rather than GSH itself.
1989
The role of the glutathione peroxidase/reductase (GSH-Px/GSSG-Rd) enzyme system in protection from paracetamol toxicity was investigated in isolated mouse hepatocytes in primary culture. The effect of inhibitors of these enzymes on the toxicity of paracetamol and on t-butylhydroperoxide (r-BOOH), used as a positive control, was determined. 1,3-Bis(chloroethyl)-1-nitrosourea (BCNU) was used to inhibit GSSG-Rd, and goldthioglucose (GTG) used to inhibit GSH-Px. Both these inhibitors increased cell membrane damage in response to oxidative stress initiated by t-BOOH. However, they also increased the susceptibility of hepatocytes to paracetarnol toxicity, indicating that a component of paracetamol's toxic effect involves formation of species that are detoxified by the GSH-Px/GSSG-Rd enzymes. To further examine the role of these enzymes, age-related differences in their activity were exploited. Hepatocytes from two-week-old mice were less susceptible to both j-BOOH and paracetamol toxicity than were those from adult mice. This corresponds to higher activity of cytosolic GSH-Px/ GSSG-Rd in this age group. However, after inhibition of GSSG-Rd with BCNU, hepatocytes from these postnatal mice were more susceptible to paracetamol toxicity. This suggests that the higher activity of GSH-Px/GSSG-Rd in hepatocytes from two-week-old mice is responsible for their reduced susceptibility to paracetamol toxicity. The data indicate that the GSH-Px/GSSG-Rd enzymes contribute to protection from paracetamol toxicity and suggest that formation of peroxides contributes to this drug's hepatotoxic effects.
…, 1994
A 67-yr-old man with chronic cardiopulmonary disease exhibited severe hepatic and moderately severe renal injury after short-term ingestion of therapeutic doses of acetaminophen (1 to 3 @day for 3 days). Drug metabolism and other studies, performed 5 mo after recovery from the acute insult, indicated that the patient had decreased rates of hepatic metabolism of acetaminophen to its primary, nontoxic metabolites and decreased kidney function that was compromised further by acetaminophen ingestion. He also had abnormally low concentrations of hepatic and plasma reduced glutathione. Alcohol abuse and malnutrition could not be implicated in the pathogenesis of injury; rather it appeared that advancing age with chronic renal, cardiac and pulmonary insufficiency contributed to acetaminophen toxicity in this patient. (HEPATOLOGY 1994; 19: 1141-1148 Acetaminophen is one of the most widely available and used antipyretic/analgesic drugs in the world because of its efficacy and relative safety. However, a large overdose of acetaminophen, often taken with suicidal intent (11, can lead to acute fulminant liver failure and death (2,3). Acetaminophen is eliminated by way of four main pathways. The two major pathways are capacity-limited processes for the formation of acetaminophen sulfate and acetaminophen glucuronide. The two minor pathways are apparent first-order processes. These include the formation of a cytochrome P-450-mediated reactive metabolite and renal excretion of unchanged