NADPH oxidase contributes to oxidative damage and mitochondrial impairment induced by acute ethanol treatment in rat hippocampal neurons.

Acute ethanol treatment induces neurodegeneration in cultured neurons and can lead to brain damage in animal models. Neuronal cells exposed to ethanol showed an increase in reactive oxygen species (ROS), oxidative damage and mitochondrial impairment contributing to synaptic failure. However, the underlying mechanisms of these events are not well understood. Here, we studied the contribution of NADPH oxidase, as a relevant source of ROS production in the brain, to mitochondrial impairment and oxidative stress induced by ethanol. We used primary hippocampal neurons subjected to an acute treatment of ethanol at increasing concentrations (25, 50, and 75 mM, 24 h), and we evaluated ROS production, mitochondrial function, and synaptic vesicle activity. Our studies showed that after ethanol administration, hippocampal neurons presented an increase in ROS levels, mitochondrial dysfunction, calcium handling defects, and synaptic impairment. Interestingly, treatment with the NADPH inhibitor, apocynin, significantly prevented oxidative stress, mitochondrial dysfunction, and the impairment of synaptic vesicle activity induced by ethanol treatment. These results indicate that NADPH oxidase could be a key participant in the molecular mechanism by which alcohol affects the brain.

ALDH2(E487K) mutation increases protein turnover and promotes murine hepatocarcinogenesis.

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) in the liver removes toxic aldehydes including acetaldehyde, an intermediate of ethanol metabolism. Nearly 40% of East Asians inherit an inactive ALDH2*2 variant, which has a lysine-for-glutamate substitution at position 487 (E487K), and show a characteristic alcohol flush reaction after drinking and a higher risk for gastrointestinal cancers. Here we report the characterization of knockin mice in which the ALDH2(E487K) mutation is inserted into the endogenous murine Aldh2 locus. These mutants recapitulate essentially all human phenotypes including impaired clearance of acetaldehyde, increased sensitivity to acute or chronic alcohol-induced toxicity, and reduced ALDH2 expression due to a dominant-negative effect of the mutation. When treated with a chemical carcinogen, these mutants exhibit increased DNA damage response in hepatocytes, pronounced liver injury, and accelerated development of hepatocellular carcinoma (HCC). Importantly, ALDH2 protein levels are also significantly lower in patient HCC than in peritumor or normal liver tissues. Our results reveal that ALDH2 functions as a tumor suppressor by maintaining genomic stability in the liver, and the common human ALDH2 variant would present a significant risk factor for hepatocarcinogenesis. Our study suggests that the ALDH2*2 allele-alcohol interaction may be an even greater human public health hazard than previously appreciated.

Investigation of the possible protective role of gallic acid on paraoxanase and arylesterase activities in livers of rats with acute alcohol intoxication.

Gallic acid, a polyphenyl class natural product from gallnut and green tea, is known to be antioxidant, anti-inflammatory and radical scavenger. In this study, we aimed to investigate the possible protective effects of gallic acid on paraoxonase and arylesterase activities in liver exposed to acute alcohol intoxication. Paraoxonase and arylesterase activities in liver tissue and serum aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase levels were measured. Histological investigations were also made. In our study, we observed a significant increase of serum alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase activities, which are indicators of liver damage after acute ethanol consumption. Gallic acid therapy has significantly reduced the increase in these biomarkers, indicating a possible hepatoprotective effect of gallic acid. Ethanol consumption caused a significant decrease in liver paraoxonase activity (P < 0.001). Gallic acid treatment partly restored this decreased paraoxonase activity, which resulted from ethanol administration. A gallic acid dose of 100 mg/kg was observed as highest restoring effect for paraoxonase activity (P < 0.05). The activity of arylesterase was decreased in the ethanol group as compared with the control group, but this was not significant. However, 50 mg/kg of gallic acid treatment restored the loss of this activity due to ethanol exposure (P < 0.001). We observed that gallic acid ameliorates the liver damage caused by excessive alcohol consumption in a dose-dependent way. Our results in this study showed that gallic acid might have a protective effect against alcoholic liver disease.

New clinical and toxicological scenario of gammaglutamyltranspeptidase.

After the discovery of gammaglutamyltranspeptidase in 1950 by Hanes, the significance of its increased levels in clinical practice has mainly been focused on ethanol toxicity, and also some neoplasms and biliary tract obstruction. More recently, attention has swift to the metabolic functions of this enzyme, as a neutralizer of oxygen free radicals and as a glutathione donor to the cell. High serum levels of gammaglutamyltranspeptidase is known to occur when oxidative stress is increased, or associated with several vascular risk factors and the insulin resistance syndrome, as an early marker of diabetes. There are also a number of drugs that induce the expression of the tissue enzyme (microsomes) with the result of high serum levels without structural damage to the liver. Because it is a ubiquitous enzyme, a very high number of causes can be involved, that may be difficult to recognize. Finally, because glutathione is necessary to conjugate a number of chemical compounds, from an epidemiological and toxicological perspective, the enzyme might be useful as a biomarker of several ambient toxins.In this review we want to emphasize the increasing clinical and diagnostic significance of this enzyme discovered half a century ago.

Effects of a preparation of combined glutathione-enriched yeast and rice embryo/soybean extracts on ethanol hangover.

The effects of a preparation of combined glutathione-enriched yeast (GEY) and rice embryo/soybean (RES) extracts (20:1), GEY/RES, on experimentally induced ethanol hangover were investigated in male Sprague-Dawley rats. To evaluate the preventive effects on hangover, rats were orally administered GEY/RES (50/2.5, 100/5, or 200/10 mg/kg) for 2 weeks. At 30 minutes after the final treatment, they were challenged with 3 mL/kg ethanol (15 mL of 20% in water/kg). The blood concentrations of alcohol and acetaldehyde were analyzed up to 7 hours postchallenge. Hepatic mRNA expression levels of alcohol-metabolizing enzymes, alcohol dehydrogenase (ADH), cytochrome P450 type 2E1 (CYP2E1), and aldehyde dehydrogenase (ALDH), were determined by real-time polymerase chain reaction. Additional rats were challenged with ethanol and, 60 minutes later, administered GEY/RES to evaluate alcohol clearance. Pretreatment with GEY/RES for 2 weeks reduced the blood concentrations of alcohol and acetaldehyde in a dose-dependent manner, lowering by 29.5% and 54.6% at the highest dose (200/10 mg/kg), respectively. The expressions of mRNAs for ADH and ALDH, the major alcohol-metabolizing enzymes, were markedly increased in the livers of rats administered GEY/RES for 2 weeks, whereas CYP2E1 mRNA was suppressed. Postchallenge treatment with GEY/RES enhanced the alcohol clearance rate by lowering blood concentrations of alcohol and acetaldehyde by 24% and 26.6%, respectively, for the highest dose group. GEY/RES remarkably eliminated 2,2-diphenyl-1-picrylhydrazyl hydrate radical and FeCl(3)-mediated lipid peroxidation in vitro and attenuated hepatic lipid accumulation following ethanol administration in vivo. Therefore, it is suggested that GEY/RES reduces the blood concentrations of alcohol and acetaldehyde not only by modulating alcohol-metabolizing enzymes, but also by exerting its antioxidant activity, and that GEY/RES could be a promising candidate for improvements of alcoholic hangover.

Impact of an acute exposure to ethanol on the oxidative stress status in the hippocampus of prenatal restraint stress adolescent male rats.

Prenatal restraint stress (PRS) in rats is associated with hippocampal dysfunctions and several behavioural and endocrine disorders related to this brain area. Recently, we have reported that the PRS modifies the hypothalamic-pituitary-adrenal (HPA) response to an ethanol challenge in adolescent animals. Since hippocampus is particularly sensitive to the deleterious effects of ethanol during adolescence, we investigated in this study the combined effects of PRS and ethanol administration on the oxidative status in the hippocampus of 28-day-old male rats. Thirty minutes after an intraperitoneal (i.p.) injection of ethanol (1.5 g/kg), the activities of several antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) but also non-enzymatic antioxidant (reduced glutathione) were assayed. Thiobarbituric acid reactive substances (TBARS) levels were also measured as a marker of lipid peroxidation. Ethanol enhanced superoxide dismutase activity in control rats but not in PRS rats. At basal level, catalase activity was lower in PRS rats than in control rats, indicating a potentially higher sensitivity to oxidative damages after this early stress. However, the hippocampal TBARS levels were not significantly affected by the ethanol administration, showing that an acute ethanol exposure does not induce oxidative damage in adolescent male rats. In conclusion, our data suggest that PRS affects both basal antioxidant status in the hippocampus and antioxidant response after an acute ethanol exposure. These findings extend previous works showing that PRS leads to hippocampal dysfunctions and raise the question of the potential increase of the hippocampal oxidative damage in PRS rats after repeated exposure to ethanol.

Estradiol protects against alteration of protein kinase C(epsilon) in a binge model of ethanol dependence and withdrawal.

This study tested the hypothesis that a binge type of ethanol intake and ethanol withdrawal disturbs protein kinase C (PKC) homeostasis in a manner protected by 17beta-estradiol. Ovariectomized rats implanted with 17beta-estradiol or oil pellets received ethanol (7.5% weight/volume, 7 days) or control solution by a gavage method. The cerebelli were collected during ethanol exposure or ethanol withdrawal to assess the activity, protein levels, and cellular distribution of PKC(epsilon) and total PKC, using an ATP phosphorylation and immunoblot assays. While both ethanol exposure and ethanol withdrawal increased membrane protein levels and membrane translocation, only ethanol withdrawal enhanced activity of PKC(epsilon). Ethanol withdrawal not ethanol exposure increased the three parameters of total PKC. 17beta-Estradiol treatment prevented these changes in PKC profiles. These data suggest that an excessive episodic intake of ethanol followed by ethanol withdrawal disturbs PKC homeostasis and cellular distribution of PKC, in particular PKC(epsilon), in a manner that is protected by estrogen. PKC(epsilon) appears more vulnerable during ethanol withdrawal than during ethanol exposure.

Alcohol intoxication impairs phosphorylation of S6K1 and S6 in skeletal muscle independently of ethanol metabolism.

BACKGROUND: The purpose of this study was to characterize the ability of alcohol to suppress insulin-like growth factor (IGF)-I stimulation of ribosomal S6 kinase 1 (S6K1) and 4E-BP1 phosphorylation, which are central elements in the signal transduction pathway used to coordinate the protein synthetic response and may contribute to the development of alcoholic myopathy. METHODS: In vivo studies examined the dose and time dependency of the ability of alcohol to impair signal transduction under basal and IGF-I-stimulated conditions. Additional studies examined the effect of gender, nutritional state, and route of alcohol administration. A separate study determined the direct effects of alcohol on muscle metabolism by using the isolated perfused hindlimb preparation. RESULTS: The phosphorylation of S6K1 and S6 in muscle was increased after injection of IGF-I in control rats. In contrast, IGF-I failed to stimulate S6K1 or S6 phosphorylation 2.5 hr after intraperitoneal administration of alcohol when the blood alcohol concentration was increased between approximately 165 and 300 mg/dl. With a maximal suppressive dose of alcohol, the inhibitory effect on S6K1/S6 phosphorylation was observed as early as 1 hr and for up to 8 hr. The ability of alcohol to impair phosphorylation of S6K1 and S6 was independent of gender (male versus female), nutritional status (fed versus fasted), and route of alcohol administration (intraperitoneal versus oral). Furthermore, the suppressive effect of alcohol was still observed in rats pretreated with 4-methylpyrazole, suggesting that the response was independent of the oxidative metabolism of ethanol. The direct effect of alcohol on IGF-stimulated S6K1/S6 phosphorylation was also present when the isolated hindlimb was perfused in situ with buffer containing alcohol. In contrast to S6K1, acute alcohol intoxication did not consistently impair the ability of IGF-I to stimulate 4E-BP1 phosphorylation under any of the experimental conditions. CONCLUSIONS: These data indicate that acute alcohol intoxication selectively impairs IGF-I signaling via S6K1, but not 4E-BP1, and that this defect is independent of gender, nutritional state, route of administration, and alcohol metabolism. The IGF-I resistance may represent a participating mechanism by which alcohol directly limits the translation of selected messenger RNAs and, ultimately, protein synthesis in skeletal muscle.

IGF-I induced phosphorylation of S6K1 and 4E-BP1 in heart is impaired by acute alcohol intoxication.

BACKGROUND: The purpose of the present study was to determine whether acute alcohol (EtOH) intoxication impairs the signal transduction pathway used to coordinate insulin-like growth factor (IGF)-I stimulation of myocardial protein synthesis. METHODS: Rats were injected intraperitoneally with EtOH or saline. After 2.5 h, IGF-I or saline was injected intravenously and the heart was excised at 2 min or 20 min. Additional rats were pretreated with RU486 or tumor necrosis factor (TNF) binding protein (BP) to assess the importance of elevations in glucocorticoids or TNF, respectively, as endogenous modulators of IGF-I signal transduction. RESULTS: EtOH did not alter the total amount or tyrosine phosphorylation of the IGF-I receptor, IRS-1 or PKB under basal or IGF-stimulated conditions. However, EtOH attenuated the ability of IGF-I to phosphorylate ribosomal S6 kinase (S6K)-1 on residues T389 ( approximately 62%) and T421/S424 ( approximately 40%), and also reduced ribosomal protein S6 phosphorylation. Under basal conditions, EtOH altered the distribution of eukaryotic initiation factor (eIF) 4E, as evidenced by a decreased amount of the active eIF4E.eIF4G complex (53%), an increased amount of inactive eIF4E.4E-BP1 complex ( approximately 3-fold), and decreased phosphorylation of 4E-BP1 (56%). EtOH also impaired the ability of IGF-I to reverse the above-mentioned changes in the eIF4E system. Pretreatment of rats with RU486 or TNFBP was unable to attenuate the EtOH-induced changes in either eIF4E distribution or the phosphorylation state of 4E-BP1, S6K1 or S6. CONCLUSIONS: These data indicate that acute EtOH intoxication alters selected aspects of translational control in the heart under basal conditions. Furthermore, despite appropriate stimulation of IGF-I receptor, IRS-1 and PKB, EtOH impairs IGF-I signaling via S6K1 and 4E-BP1 pathways, and this defect is regulated in a glucocorticoid- and TNF-independent manner. This IGF-I resistance may represent a participating mechanism by which alcohol limits protein synthesis in heart.

Alcohol metabolism: role in toxicity and carcinogenesis.

This article contains the proceedings of a symposium at the 2002 RSA Meeting in San Francisco, organized and co-chaired by Thomas M. Badger, Paul Shih-Jiun Yin, and Helmut Seitz. The presentations were (1) First-pass metabolism of ethanol: Basic and clinical aspects, by Charles Lieber; (2) Intracellular CYP2E1 transport, oxidative stress, cytokine release, and ALD, by Magnus Ingelman-Sundberg; (3) Pulsatile ethanol metabolism in intragastric infusion models: Potential role in toxic outcomes, by Thomas M. Badger and Martin J.J. Ronis; (4) Free radicals, adducts, and autoantibodies resulting from ethanol metabolism: Role in ethanol-associated toxicity, by Emanuele Albano; and (5) Gastrointestinal metabolism of ethanol and its possible role in carcinogenesis, by Helmut Seitz.

Effect of chronic alcohol consumption on the ethanol- and acetaldehyde-metabolizing systems in the rat gastrointestinal tract.

The activities of alcohol dehydrogenase (ADH), catalase, microsomal ethanol-oxidizing system (MEOS) and aldehyde dehydrogenase (ALDH) were measured in gastric, small intestinal, colonic and rectal mucosal samples of rats fed on a liquid alcohol diet for 1 month. In the rectum and large intestine of control animals, the activities of ADH, MEOS and catalase were maximal, whereas the activity of ALDH was minimal. After chronic alcohol intoxication, MEOS activity increased significantly in the stomach. An activation of catalase and MEOS and a decrease of the low-K(M) ALDH activity were observed in the rectum of experimental animals. In rats consuming the alcohol diet, hypertrophy of crypts and an increased number of mitoses were noticed in colonic and rectal mucosa. Acute alcohol intoxication (2 g/kg, intragastrically) produced significantly higher acetaldehyde concentrations in the contents of the large intestine and rectum of rats receiving alcohol chronically compared to controls. Thus, after chronic alcohol intoxication, the large intestine regions showed a greater imbalance between the activities of acetaldehyde-producing and -oxidizing enzymes, which resulted in accumulation of acetaldehyde. This mechanism can account for the local toxicity of ethanol after its chronic consumption, and relates the development of mucosal damage and compensatory hyper-regenerative processes, and possibly carcinogenesis, in the colonic and rectal mucosae of alcoholics to the effects of acetaldehyde.

Factors involved in hepatic glutathione depletion induced by acute ethanol administration.

Factors implicated in changes of the hepatic glutathione concentration following acute ethanol administration were examined in rats. Adult female rats were treated with either ethanol (4 g/kg, p.o.) or an isocaloric glucose solution. The hepatic reduced glutathione (GSH) concentration decreased rapidly after ethanol intake with a maximum diminution, approximately 50% of the control value, being observed at t = 6 h. The hepatic GSH concentration gradually increased, and finally rebounded at 24 h after ethanol ingestion. The dose of ethanol induced a transient increase in the oxidized glutathione (GSSG)/GSH ratio, which was associated with a significant reduction in GSH rather than elevation in GSSG [corrected]. The activity of gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme for glutathione synthesis, and the cysteine concentration in liver were also measured. The GCS activity was depressed to approximately 80% of the control value at t = 2.5 h followed by rapid recovery, but no difference in the hepatic cysteine concentration between control and ethanol treated rats was observed for 24 h, suggesting that the reduction in glutathione synthesis may not play a major role in the significant depletion of this tripeptide in liver. The total glutathione concentration was measured both in prehepatic and posthepatic inferior vena cava blood. The glutathione concentration in posthepatic blood was approximately twice as high as that of prehepatic blood in control rats. Acute ethanol administration doubled the elevation of glutathione in posthepatic blood measured at t = 2.5 h. The sinusoidal efflux of glutathione estimated from the increase in blood glutathione concentration was greater than the total amount of its depletion in the liver of rats treated with ethanol. The results suggest that in the liver of rats treated acutely with ethanol, glutathione efflux plays the most important role in the reduction of this tripeptide, which would be aggravated by a transient decrease in glutathione synthesis and by increased consumption in association with its metabolism.

[Glutathione reductase activation in acute alcoholic intoxication]. / Aktyvatsiia hlutationreduktazy za umov hostroï alkohol'noï intoksykatsiï.

Experiments carried out on rats were aimed to study the effect of acute alcohol intoxication on activity of cytoplasmic and mitochondrial forms of glutathione reductase. It has been found that alcohol activates the enzyme. The in vitro experiments have confirmed the effect. The correlation between the activity of the studied enzyme and the content of various forms of endogenous flavines is observed. It is stated that an increase in the alcohol dehydrogenase activity in tissues of rats under study induces a drastic rise of the number of restored nicotinamide coenzymes and as a result of this the glutathione reductase activity grows.

[Evaluation of an increased blood level of GGT, CDT, methanol, acetone and isopropanol in alcohol intoxicated automobile drivers. Alcoholism indicators instead of medical-psychological examination]. / Zur Wertung erhöhter Spiegel von GGT, CDT, Methanol, Aceton und Isopropanol im Blut alkoholauffälliger Kraftfahrer. Alkoholismusindikatoren anstelle medizinisch-psychologischer Untersuchungen?

Several thousand blood samples were taken from alcoholized drivers at the Blood Alcohol Examination Centre of the Institute of legal Medicine at Cologne University. These samples showed blood alcohol contents (BAC) as well as GGT, CDT, methanol, acetone and isopropanol levels which indicated alcohol addiction. The blood samples were selected by the drivers' ages and their BAC, but in some cases the GGT also played a role. In the majority of cases 1 or 2 parameters were measured. In 200 cases all four indicators were determined. The four parameters characterize a different problematic drinking behaviour. GGT characterizes chronic, long-term misuse, CDT characterizes occasional misuse, methanol characterizes current addicted drinking and acetone and isopropanol characterize metabolic disorders caused by alcohol. The importance of parameters is thoroughly discussed, also in relation to incorrectly measured positive values and the relation between alcohol consumption and -problems. Methanol values above 10 mg/kg, GGT activities above 100 U/l and CDT levels above 60 U/l provide sufficient proof of there being an alcohol problem which requires treatment. The levels of other indicators need not be above normal to determine this. The proportion of drivers under the influence of alcohol with problematic alcohol levels increases significantly when the BAC is above 2.0 per mille. However, there have been drivers with alcohol problems with lower BAC levels. DUI offenders addicted to alcohol are quite frequently over 40 years old. A correlation between the single indicators and the BAC is rarely found. If a correlation is to be found, it would be most likely with drivers whose BAC lies above 2.0 per mille. The mentioned indicators would detect an alcohol problem from the blood sample taken for the blood alcohol test. Alcohol problems may be detected and treated shortly after the DUI offence. This method is comparatively cheaper than medical-psychological-examinations as well as being based on objective and verifiable parameters.

[The action of acute alcoholic intoxication on the antioxidant system and creatine kinase activity in the brain of rat embryos]. / Deistvie ostroi alkogol'noi intoksikatsii na antioksidantnoi sistemu i aktivnost' kreatinkinazy v mozge émbrionov krys.

The activity of superoxide dismutase (SOD) was enhanced in the brain of 14-day rat embryos 1 and 3 hours after single administration of ethanol to pregnant rats. Concurrently, the levels of lipid peroxidation were changing in these periods. Ethanol, 1 g/kg, increased LPO levels in the 14-day embryonic brain, whereas its dose of 3 g/kg decreased them. It is concluded that with single administration of ethanol, free-radical processes are activated in the embryonic brain. It is suggested that the activity of creatine kinase decreases concurrently with an increase in SOD activity due to the damaging action of superoxide radicals on the enzyme molecule.

Disturbances in myocardial creatine kinase following ethanol administration to rats--trials of prevention by allopurinol, desferrioxamine and propranolol.

A significant decrease in myocardial creatine kinase (CK) activity is apparent 2 hr after an acute ethanol load (2.3 g/kg, i.p.) in the rat. A lower dose (1.15 g/kg, i.p.), as well as ethanol addition in vitro up to 50 mM, do not affect this activity. Pretreatment with allopurinol (146 mumols/kg, i.p.) given at 16 hr and at 30 min before ethanol (2.3 g/kg) or with desferrioxamine (152 mumols/kg, i.p.) 30 min before ethanol failed to prevent the ethanol-induced decrease in CK activity. By contrast, propranolol (17 mumols/kg, i.p.), administered 30 min before ethanol elicited an enhanced CK activity in both control and ethanol-treated rats. This finding is likely related to the beta-blocking action and/or antioxidant properties of propranolol. Chronic ethanol intake (18% in calories) for 4 weeks also induced a decrease in myocardial CK activity, which could play a role in the pathogenesis of alcoholic cardiomyopathy.

Buthionine sulfoximine inhibition of glutathione biosynthesis enhances hepatic lipid peroxidation in rats during acute ethanol intoxication.

A single intraperitoneal injection of DL-buthionine-S,R-sulfoximine (BSO) (4 mmol/kg) to overnight-starved rats caused a 70% inhibition of hepatic gamma-glutamylcysteine synthetase and induced a decrease in liver-reduced glutathione (GSH) for several hours. There was, however, no difference in hepatic lipid peroxidation, as assessed by malondialdehyde accumulation, between the control and BSO groups. During acute ethanol intoxication (5 g/kg), hepatic lipid peroxidation was increased by approx. 40% within 6 hr. Hepatic [GSH] was also significantly decreased by ethanol. The effect of ethanol on GSH level was not observed in rats pretreated with BSO, though the ethanol-induced enhancement of hepatic lipid peroxidation was potentiated by the BSO pretreatment. Under these conditions there were no apparent effects on blood concentrations of ethanol and acetaldehyde nor on activities of hepatic alcohol dehydrogenase, aldehyde dehydrogenase, glutathione-dependent detoxifying enzymes, superoxide dismutase or catalase. These results suggest that, although a decrease (by BSO) in GSH by itself does not alter the degree of endogenous lipid peroxidation, it is associated with a potentiation of the enhancement of hepatic lipid peroxidation caused by acute ethanol intoxication.

Influence of acute ethanol administration on hepatic glutathione metabolism in the rat.

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.

Prolyl hydroxylase activity in liver and serum of rats and human subjects intoxicated by chronic administration of ethanol.

It was found that chronic intoxication of rats with ethanol results in an increase in prolyl hydroxylase activity in liver and serum of the investigated animals. Similar effects have been observed in some alcoholic patients. We hope that the assay of prolyl hydroxylase in serum or in liver biopsy samples might be useful for the diagnosis and prognosis of the tendency of some individuals to develop liver cirrhosis.