PLASMA AMINO ACID PATTERNS IN ALCOHOLISM: THE EFFECTS OF ETHANOL LOADING

Longitudinal Associations of Adherence to the Dietary World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) and Dutch Healthy Diet (DHD) Recommendations with Plasma Kynurenines in Colorectal Cancer Survivors after Treatment

The tryptophan-kynurenine pathway has been linked to cancer aetiology and survivorship, and diet potentially affects metabolites of this pathway, but evidence to date is scarce. Among 247 stage I-III CRC survivors, repeated measurements were performed at 6 weeks, 6 months, and 1 year post-treatment. Adherence to the World Cancer Research Fund/ American Institute for Cancer Research (WCRF) and Dutch Healthy Diet (DHD) recommendations was operationalized using seven-day dietary records. Plasma kynurenines of nine metabolites were analysed. Longitudinal associations of adherence to these dietary patterns and plasma kynurenines were analysed using confounder-adjusted linear mixed-models. In general, higher adherence to the dietary WCRF/AICR and DHD recommendations was associated with lower concentrations of kynurenines with pro-oxidative, pro-inflammatory, and neurotoxic properties (3-hydroxykynurenine (HK) and quinolinic acid (QA)), and higher concentrations of kynurenines with anti-oxidative, anti-inflammatory, and neuroprotective properties (kynurenic acid (KA) and picolinic acid (Pic)), but associations were weak and not statistically significant. Statistically significant positive associations between individual recommendations and kynurenines were observed for: nuts with kynurenic-acid-to-quinolinic-acid ratio (KA/QA); alcohol with KA/QA, KA, and xanthurenic acid (XA); red meat with XA; and cheese with XA. Statistically significant inverse associations were observed for: nuts with kynurenine-to-tryptophan ratio (KTR) and hydroxykynurenine ratio; alcohol with KTR; red meat with 3-hydroxyanthranilic-to-3-hydroxykynurenine ratio; ultra-processed foods with XA and KA/QA; and sweetened beverages with KA/QA. Our findings suggest that CRC survivors might benefit from adhering to the dietary WCRF and DHD recommendations in the first year after treatment, as higher adherence to these dietary patterns is generally, but weakly associated with more favourable concentrations of kynurenines and their ratios. These results need to be validated in other studies.

Alcohol Consumption and Tryptophan Metabolism Among People with HIV Prior to Antiretroviral Therapy Initiation: The Uganda ARCH Cohort Study

AIMS

Alcohol is hypothesized to have effects on the kynurenine pathway of tryptophan catabolism, a potential mechanism for alcohol-induced depression and aggression. A biomarker of this pathway, the plasma kynurenine to tryptophan ratio (K/T ratio), has been associated with HIV progression, mortality and depression. Our aim was to assess whether hazardous alcohol consumption is associated higher K/T ratio among people with HIV.

METHODS

Participants were a subset of the Uganda Alcohol Research Collaboration on HIV/AIDS Cohort. Alcohol consumption was categorized (abstinent, moderate and hazardous alcohol use) using the Alcohol Use Disorders Identification Test-Consumption and phosphatidylethanol (PEth). K/T ratio was the primary outcome. We used linear regression adjusted for age, sex, FIB-4, hepatitis B surface antigen, log (HIV viral load) to estimate the association between alcohol consumption and K/T ratio.

RESULTS

Compared to abstinent participants, hazardous drinkers and moderate drinkers had higher K/T ratio but these differences did not reach statistical significance.

CONCLUSIONS

Our results suggest that hazardous alcohol consumption, in the context of untreated HIV infection, may not significantly alter kynurenine to tryptophan ratio as a measure of activity of the kynurenine pathway of tryptophan metabolism.

Plasma tryptophan and kynurenine pathway metabolites in abstinent patients with alcohol use disorder and high prevalence of psychiatric comorbidity

BACKGROUND

Alterations in tryptophan (TRP) metabolism has been linked to drug exposure and mental disorders. However, most of studies have been performed without considering the co-occurrence of both disorders in the context of addiction. This cross-sectional study examines TRP metabolism through the serotonin (5-HT) and kynurenine (KYN) pathways in subjects with alcohol use disorders (AUD) and high prevalence of psychiatric comorbidity.

METHODS

For this purpose, male and female abstinent AUD patients (N = 130) and healthy controls (N = 80) were clinically evaluated for substance use and mental disorders, and blood samples were collected to determine plasma concentrations of TRP, 5-HT, KYN and kynurenic acid (KA) using high performance liquid chromatography. Clinical and biochemical variables were analyzed for potential associations considering AUD, psychiatric comorbidity and sex.

RESULTS

TRP concentrations were significantly associated with an interaction effect between AUD diagnosis and sex (p < .01): TRP concentrations were lower in male AUD patients but higher in female AUD patients compared with their controls. KYN and KA concentrations were significantly associated with AUD diagnosis (p < .01 and p < .05, respectively). Thus, AUD patients showed significantly higher KYN concentrations and lower KA concentrations than controls. Regarding 5-HT concentrations, there were sex differences in the alcohol group (p < .05) and female AUD patients showed lower 5-HT concentrations than male AUD patients. Moreover, there was a significant interaction effect between psychiatric comorbidity and sex on TRP concentrations in the alcohol group (p < .01). Whereas male patients with both comorbid substance use and mental disorders showed lower TRP concentrations than male non-comorbid patients, female patients with comorbid mental disorders showed higher TRP concentrations than female non-comorbid patients.

CONCLUSION

While alterations in the KYN pathway appear to be directly associated with a history of AUD, altered TRP concentrations are associated with the presence of comorbid psychiatric disorders. Finally, sex differences in TRP metabolism must be considered in future studies.

Tryptophan metabolism in alcoholism

Acute and chronic alcohol (ethanol) intake and subsequent withdrawal exert major effects on tryptophan (Trp) metabolism and disposition in human subjects and experimental animals. In rats, activity of the rate-limiting enzyme of Trp degradation, liver Trp pyrrolase (TP), is enhanced by acute, but inhibited after chronic, ethanol administration, then enhanced during withdrawal. These changes lead to alterations in brain serotonin synthesis and turnover mediated by corresponding changes in circulating Trp availability to the brain. A low brain-serotonin concentration characterizes the alcohol-preferring C57BL/6J mouse strain and many alcohol-preferring rat lines. In this mouse strain, liver TP enhancement causes the serotonin decrease. In man, acute ethanol intake inhibits brain serotonin synthesis by activating liver TP. This may explain alcohol-induced depression, aggression and loss of control in susceptible individuals. Chronic alcohol intake in dependent subjects may be associated with liver TP inhibition and a consequent enhancement of brain serotonin synthesis, whereas subsequent withdrawal may induce the opposite effects. The excitotoxic Trp metabolite quinolinate may play a role in the behavioural disturbances of the alcohol-withdrawal syndrome. Some abstinent alcoholics may have a central serotonin deficiency, which they correct by liver TP inhibition through drinking. Further studies of the Trp and serotonin metabolic status in long-term abstinence in general and in relation to personality characteristics, alcoholism typology and genetic factors in particular may yield important information which should facilitate the development of more effective screening, and preventative and therapeutic strategies in this area of mental health.

Activation of liver tryptophan pyrrolase mediates the decrease in tryptophan availability to the brain after acute alcohol consumption by normal subjects

AIMS

We have previously suggested that acute ethanol consumption by normal subjects decreases the availability of circulating tryptophan (Trp) to the brain by activating liver Trp pyrrolase, the first and rate-limiting enzyme of the (major) kynurenine pathway of Trp degradation. The aim of the present study was to examine this hypothesis further by measuring plasma levels of kynurenine metabolites following alcohol consumption.

METHODS

After an overnight fast and a light breakfast, each of 10 healthy subjects received one of five drinks (placebo and doses of ethanol of 0.2, 0.4, 0.6 and 0.8 g/kg body weight in tonic water) on five different occasions. Blood samples were withdrawn 2 h later and plasma was analysed for concentrations Trp, competing amino acids (CAA) and kynurenine metabolites.

RESULTS

Along with the depletion of plasma Trp and the decrease in its availability to the brain, as expressed by the ratio of [Trp]/[CAA], plasma kynurenine was elevated by doses of ethanol of 0.2-0.8 g/kg body weight. The ratio% of [kynurenine]/[Trp], an index of the expression of Trp pyrrolase activity, was also increased by all doses of ethanol.

CONCLUSIONS

We conclude that activation of liver Trp pyrrolase mediates the depletion of plasma Trp and the decrease in its availability to the brain induced by acute ethanol consumption.

Alcohol and violence and the possible role of serotonin

BACKGROUND

There is undisputed evidence linking alcohol consumption and violence and other forms of aggressive behaviour, and also linking aggression with dysfunction of the brain indolylamine serotonin (5-hydroxytryptamine or 5-HT). Alcohol consumption also causes major disturbances in the metabolism of brain serotonin. In particular, acute alcohol intake depletes brain serotonin levels in normal (non-alcohol-dependent) subjects. On the basis of the above statements, it is suggested that, at the biological level, alcohol may induce aggressive behaviour in susceptible individuals, at least in part, by inducing a strong depletion of brain serotonin levels.

AIMS

In this article, evidence supporting these interrelationships and interactions will be summarized and discussed, the alcohol serotonin aggression hypothesis will be reiterated, and potential intervention strategies will be proposed.

Different diets and amino acid supplementation do not affect the voluntary consumption of ethanol by rats

The effects of four different diets (control diet: 19.5% protein, 60.5% carbohydrate, 10% fat; diet I: 65% protein, 10% carbohydrate, 10% fat; diet II: 5% protein, 76% carbohydrate, 10% fat; diet III: 20% protein, 69% carbohydrate, 1% fat; diet IV: 69% protein, 15% carbohydrate, 1% fat) and supplementation with 3 amino acids (tryptophan: 150 mg/kg/d; arginine: 400 mg/kg/d; taurine: 380 mg/kg/d) on the voluntary consumption of ethanol were investigated in rats using the 2 bottle method. First, rats received the control diet and diets I, II, III and IV for 20 days with a choice of ethanol for the last 6 days only. Ethanol consumption was similar in all dietary groups. Second, rats received the control diet for 8 days followed by diets I, II and IV for another 8 days. Ethanol was offered throughout both periods. The switch to the special diets did not affect ethanol consumption. Third, rats received a control diet with arginine, tryptophan or taurine added to the drinking fluids for 16 days with a choice of ethanol for the last 5 days; thereafter supplementation stopped but the ethanol choice remained. No difference in the voluntary intake of ethanol was noted but ethanol consumption fell after cessation of arginine supplementation. In conclusion, diets differing greatly in their composition or supplementation with these 3 amino acids did not affect the voluntary choice of ethanol by rats in a significant manner.

Formation of propionate after short-term ethanol treatment and its interaction with the carnitine pool in rat

Organic acidurias are genetic disorders of mitochondrial metabolism that lead to the accumulation in tissues and biological fluids of organic acids. It has been demonstrated that interaction of carnitine with the cellular CoA pool, through the production of acyl-carnitines, is potentially critical for maintaining normal cellular metabolism under conditions of impaired acyl-CoA use and that exposure of humans and other mammals to ethanol effects leads to impairment of mitochondrial function. The aim of the present study was to evaluate the role of ethanol on urinary excretion of short-chain organic acids and endogenous carnitines in rats. The data reported show that ethanol significantly increases urinary excretion of propionate, methylmalonate, as well as free acetate, butyrate, pyruvate, lactate, and beta-hydroxybutyrate. Furthermore, the increased formation of propionate and methylmalonate was dependent on the dose of ethanol; did not require the metabolism of ethanol, as was shown in experiments with pyrazole treatment of ethanol rats; and appears to be mediated by beta-adrenergic mechanisms because propranolol almost completely suppresses propionate accumulation. Alcohol administration also increased excretion of specific acyl-carnitines, corresponding to the accumulating acyl groups, whereas excretion of free carnitine was significantly reduced, with respect to control values. The data presented indicate that the short-term ethanol administration is associated with increased excretion of selected organic acids. This study suggests that endogenous carnitine pool might play a role against the deleterious effects of accumulating short-chain organic acids.

Serotonin-immune interactions in detoxified chronic alcoholic patients without apparent liver disease: activation of the inflammatory response system and lower plasma total tryptophan

The aims of the present study were to examine (1) the inflammatory response system (IRS), through measurements of serum interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), sgp130 (the soluble form of the IL-6 transducer signal protein), CC16 (Clara Cell protein; an endogenous anti-cytokine), IL-1R antagonist (IL-1RA), IL-8 and sCD14; and (2) the availability of plasma total tryptophan to the brain in chronic alcoholic patients without apparent liver disease (AWLD). Detoxified AWLD patients had significantly lower plasma tryptophan and serum CC16 and significantly higher serum IL-1RA and IL-8 concentrations than normal volunteers. There were significant correlations between the availability of tryptophan to the brain and serum IL-6, IL-8 and IL-1RA (all negative) and CC16 (positive). The results suggest that (1) there is, in detoxified AWLD patients, an activation of the monocytic arm of cell-mediated immunity and a lowered anti-inflammatory capacity of the serum; and that (2) lower availability of plasma tryptophan to the brain in detoxified AWLD patients is related to activation of the IRS. Lower CC16 may be one factor predisposing chronic alcoholic patients toward infectious disorders.

Tryptophan metabolism and disposition in relation to alcohol and alcoholism

Tryptophan (Trp) metabolism and disposition in relation to alcohol and alcoholism are briefly reviewed. The changes observed could generally be classified into those: (1) exerted by acute or chronic alcohol administration and/or subsequent withdrawal; (2) already present in the absence of alcohol consumption, such as in naive alcohol-preferring animals or in abstinent alcoholics. In normal rats, acute ethanol administration activates liver Trp pyrrolase and exerts a biphasic effect on brain 5-HT (5-hydroxytryptamine or serotonin) synthesis, whereas chronic ethanol administration and subsequent withdrawal exert opposite effects on 5-HT synthesis mediated by corresponding changes in liver Trp pyrrolase activity. A cerebral 5-HT deficiency has been demonstrated in the alcohol-preferring C57BL mouse strain and in a number of alcohol-preferring rat lines, the mechanism of which is understood only in two models; the C57B1 mouse strain has a higher liver Trp pyrrolase activity and the P rat line from Indiana has a lower density of serotonergic fibres in cerebral cortex. In man, acute ethanol intake lowers circulating [Trp] and its availability to the brain, almost certainly by activating liver Trp pyrrolase. Some evidence exists for possible inhibition of pyrrolase activity in non-abstinent chronic alcoholics. Evidence in recently abstinent alcoholics suggests that Trp availability to the brain may be impaired and that this may be particularly so in patients with positive family history. Exploration of this latter possibility may be important in understanding the biological basis of predisposition to alcoholism.

Ethanol elevates fetal serum glutamate levels in the rat

Glutamate is an important excitatory neurotransmitter. However, a sustained elevation of glutamate in the extracellular space may be toxic to neurons. Because the blood-brain barrier is incomplete in the developing fetus, an elevation of fetal serum glutamate could expose the immature, growing brain to potentially toxic levels of extracellular glutamate. Chronic ethanol consumption during pregnancy is associated with an increased risk for a complex array of congenital anomalies, including alterations in the CNS, a hallmark of the fetal alcohol syndrome. Some central nervous system changes appear to involve the glutamate receptor, including reduced number and altered function. One mechanism for receptor downregulation may be a sustained elevation in extracellular glutamate. We hypothesize that chronic ethanol exposure during pregnancy leads to an elevation in fetal serum glutamate. When rats were fed ethanol-containing liquid diet throughout pregnancy, growth retardation of fetuses was observed at sacrifice (gestation day 20). Within each group, ethanol-fed, pair-fed, and ad libitum chow-fed, serum glutamate levels were generally higher in the fetus than in the dam. Ethanol treatment had no effect on fetal or maternal serum glutamine, a reciprocal metabolite of glutamate. In contrast, ethanol treatment increased serum glutamate levels in the fetal serum by nearly 50%, compared with either of the control groups. Maternal serum glutamate was not affected. The finding of ethanol-induced elevation of fetal serum glutamate suggests that the developing brain might be concurrently exposed to elevated levels of extracellular glutamate. Chronic exposure to elevated glutamate during critical periods of brain development may contribute to the pathogenesis of the fetal alcohol syndrome.

Similar effects of ethanol and tert-butanol on amino acid concentrations in rat serum and liver

Both metabolic and nonmetabolic mechanisms have been proposed to the plasma amino acid decreasing effect of an acute ethanol load. We used tert-butanol, an alcohol that is only minimally metabolized, as a tool to explain the mechanism behind the amino acid decreasing effect of ethanol. Acute administration of tert-butanol was found to exert a decreasing effect on rat serum amino acid concentrations similar to that of ethanol, indicating that the mechanism of the amino acid decreasing effect of ethanol is primarily due to ethanol itself and not to its oxidation. Ethanol and tert-butanol also had similar effects on liver amino acid concentrations, including an increase in the glycine concentration and decrease in the concentrations of glutamate, alanine, leucine, and tyrosine.

Laboratory markers of ethanol intake and abuse: a critical appraisal

Laboratory markers for ethanol intake and abuse and chronic alcoholism currently in use have been critically reviewed. The merits and pitfalls of each test have been evaluated. The clinical use of the new test of carbohydrate-deficient transferrin has been particularly emphasized. Carbohydrate-deficient transferrin currently provides the highest specificity and sensitivity of all commonly used markers of alcoholism.

Development of tolerance to the plasma amino acid-decreasing effect of ethanol in the rat

Male Sprague-Dawley rats were treated for one month with daily intraperitoneal injections of ethanol (2 g kg-1), or saline. After this pretreatment, animals from each group were given acute doses of ethanol (2 g kg-1) or saline. Plasma amino acid concentrations and brain tyrosine, tryptophan, dopamine, 5-HT and 5-HIAA concentrations were measured in samples collected 1 h after the injections. Acute administration of ethanol induced a dramatic fall in the concentrations of 18 out of 20 plasma amino acids in animals pretreated with saline. In animals chronically pretreated with ethanol this decrease was much smaller. Furthermore, the decrease was significantly lower for 6 of the measured amino acids in the chronic ethanol group compared with the saline-treated control group. Tolerance to the plasma amino acid decreasing effect of ethanol had thus developed. This acquired tolerance might be explained by both pharmacokinetic and pharmacodynamic mechanisms. Chronic administration of ethanol induced increased concentrations of tyrosine and dopamine in the brain, probably due to increased transport of tyrosine into the brain caused by an increase in the ratio of tyrosine to large neutral amino acids in plasma.

Alcohol and related dietary effects on mouse natural killer-cell activity

Natural killer (NK) cell activity of spleen cells from female C57BL/6 mice receiving 10% w/v alcohol solution for 4 weeks was studied in mice fed a nutritionally complete crystalline amino-acid diet and in mice fed diets moderately deficient in (i) tyrosine and phenylalanine or (ii) methionine. Natural killer cell activity was determined in a 4-hr cytolytic chromium-release assay against YAC-1 lymphoma cells. Alcohol consumption did not effect NK cell-mediated lysis irrespective of nutritional status; however, NK-cell activity was depressed in mice fed the tyrosine- and phenylalanine-deficient diet and was enhanced in mice fed the methionine-deficient diet. These data suggest that the changes in immune function often observed in alcoholics may be more closely linked to dietary and nutritional status than to the direct effects of the ingested alcohol.

Effect of ethanol on rat brain protein synthesis. I. Acute administration

The addition of ethanol to cell free protein synthesizing systems from the rat brain in vitro did not influence the incorporation of labeled amino acids into acid precipitable protein within a concentration range up to 10 mM. But in vivo acute administration of the drug to naive animals induced an activation of protein synthesis by cytoplasmic ribosomes isolated from the cerebral cortex and cerebellum. By contrast, incorporation of amino acids into mitochondrial or synaptosomal protein remained unchanged. The stimulating effect of ethanol on brain protein synthesis was connected with increased charging levels of brain transfer ribonucleic acids, which were initially confined to leucyl-tRNA. The activated agent was bound to the soluble enzyme fractions used in the cell-free systems.

Plasma amino-acid patterns in liver disease

Plasma amino-acid concentrations were measured in 167 patients with liver disease of varying aetiology and severity, all free of encephalopathy, and the results compared with those in 57 control subjects matched for age and sex. In the four groups of patients with chronic liver disease (26 patients with chronic active hepatitis, 23 with primary biliary cirrhosis, 11 with cryptogenic cirrhosis, and 48 with alcoholic hepatitis +/- cirrhosis) plasma concentrations of methionine were significantly increased, while concentrations of the three branched chain amino-acids were significantly reduced. In the first three groups of patients plasma concentrations of aspartate, serine, and one or both of the aromatic amino-acids tyrosine and phenylalanine were also significantly increased, while in the patients with alcoholic hepatitis +/- cirrhosis plasma concentrations of glycine, alanine, and phenylalanine were significantly reduced. In the three groups of patients with minimal, potentially reversible liver disease (31 patients with alcoholic fatty liver, 10 with viral hepatitis, and 18 with biliary disease) plasma concentrations of proline and the three branched chain amino-acids were significantly reduced. Patients with alcoholic fatty liver also showed significantly reduced plasma phenylalanine values. Most changes in plasma amino-acid concentrations in patients with chronic liver disease may be explained on the basis of impaired hepatic function, portal-systemic shunting of blood, and hyperinsulinaemia and hyperglucagonaemia. The changes in patients with minimal liver disease are less easily explained.

Plasma alpha-amino-n-butyric acid/leucine ratio in alcoholics

Fasting free amino acid concentrations in plasma of 20 control and 18 alcoholic subjects were compared in an attempt to validate previous reports that the molar ratio of alpha-amino-n-butyric acid/leucine (A/L ratio) is a marker for alcoholism. We were unable to confirm the observations of either altered alpha-amino-n-butyric acid or leucine concentrations or an increased A/L ratio in alcoholic subjects, and we conclude that the A/L ratio is not a biochemical marker for alcoholism.

Amino acid changes in a genetic strain of epileptic beagle dogs

A neurochemical evaluation of beagle dogs with naturally occurring spontaneous generalized convulsive seizures was performed. Amino acid profiles of serum, cerebrospinal fluid (CSF), and biopsied cerebral cortex from epileptic dogs were compared with those from seizure-free siblings. No differences in absolute levels were noted. However, when levels were normalized as a percent of total free amino acids, seizures was performed. Amino acid profiles of serum, cerebrospinal fluid (CEF), and biopsied cerebral cortex from epileptic dogs were compared with those seizure-free siblings. No differences also the two groups differed in certain respects. Ten significant correlations between amino acid pairs appeared in epileptic dogs, but only one was seen in seizure-free animals. Seven of these ten correlations involved glutamate or taurine. It was noted that the highly correlated amino acids (taurine, glutamate, glycine, glutamine, alanine) all utilize sodium-dependent membrane transport processes. The sum of glutamate, aspartate, and glycine levels (competing sodium-dependent high-affinity systems) was significantly lower in epileptic beagles. Since this difference was noted in serum but not CSF or brain, it may indicate a diminished capacity of sodium-dependent high-affinity renal transport for acidic and certain small neutral amino acids.

Markers for detecting alcoholism and monitoring for continued abuse

Several biochemical and haematological abnormalities are associated with excessive alcohol intake and some are used in the recognition and management of alcoholics. The ideal biological marker for detecting and monitoring alcoholics should be sensitive and highly specific for alcohol abuse; its value should be affected by changes in alcohol intake over relatively short periods of time and it should be quick, simple, convenient and inexpensive to estimate. At the present time no simple reliable marker is available which fulfills these criteria. Measurements of serum aspartate transaminase, serum gamma-glutamyl-transpeptidase and mean corpuscular volume are of proven value however and the majority of alcoholics can be detected and monitored by combining the measurements of these three tests. Blood/breath alcohol measurements are of limited value for detection but are useful for follow up. Measurement of the plasma alpha-amino-n-butyric acid/leucine ratio is of disputed value and not likely to be of great practical use. Measurement of serum alpha-lipoproteins, erythrocyte delta-aminolaevulinic acid dehydrase activity and qualitative estimation of serum transferrin have all been proposed as markers for alcohol abuse and are currently under evaluation.

Hypoglycemic coma with ketoacidosis in nondiabetic alcoholics

Five nondiabetic, chronically alcoholic patients presented in a comatose state during a two month prospective study and were found to be ketoacidotic. All of the patients were men, 28 to 59 years old. The usual history was one of chronic heavy, daily alcohol consumption until one to three days before presentation, when persistent anorexia, abdominal distress, nausea and vomiting commenced, with abstention from food thereafter. The patients were found to be in hypoglycemic coma, with diaphoresis, tachypnea and tachycardia, and immediately awoke when intravenous infusion of glucose was started. Serum glucose ranged between 19 and 27 mg per dl, the average arterial pH was 7.19 and the mean anion gap was 25 mEq per liter. Reaction with Acetest tablets was positive for ketones in both serum and urine in three of the patients. Serum beta-hydroxybutyrate was elevated in the four patients in whom it was measured. Lactic acidosis was not present. All patients were managed with prolonged intravenous infusions of glucose and saline solutions, and within 12 to 18 hours they were feeling well and findings on serum chemistry studies were normal. Follow-up after three months showed no repeated difficulties. The combination of alcoholic ketoacidosis and hypoglycemic coma in nondiabetic persons has not been described in the literature as a clinical entity; it may, however, represent a common but unrecognized syndrome. Therefore, because of its potentially serious consequences and because treatment is simple and effective, this entity must be thought of in alcoholic patients with altered mental status.

Effects of acute and chronic ethanol administration on amino acid metabolism in rabbit brain and blood

Acute administration of ethanol increased the cerebrocortical amino acids derived through the tricarboxylic acid cycle except for GABA and decreased the plasma alanine, valine, isoleucine, leucine, and phenylalanine whereas chronic administration of ethanol caused no significant changes in the cerebrocortical amino acids and increased the plasma glutamic acid, glutamine, glycine, and ornithine, with decreases in taurine and phenylalanine. Result of this experiment suggests that the CNS-depressant effect of ethanol is related to changes in the GABA system and increased uptake by the brain of the branched-chain amino acids while the development of tolerance to ethanol is associated with cellular adaptation in the CNS.

Plasma and urinary amino acids in primary gout, with special reference to glutamine

Measurement of the plasma free amino acids by column chromatography (AutoAnalyzer) in 32 patients with primary gout showed statistically significant increases or decreases in several components when compared with the spectrum in 18 control subjects, but the absolute amounts involved were small and the mean total plasma amino acid concentrations in both groups were the same. In the urine all major amino acid components, notably glutamine, serine, threonine, and leucine, were lower in our gouty than in our nongouty subjects, as were also the corresponding renal clearance ratios. These deficits could be reproduced by restricting dietary protein, so appear to be due largely to the some-what reduced mean dietary protein intake of our gouty subjects. However, the low renal clearance of glutamine, the most striking and consistent of the deficits in urinary amino acids noted, could not be accounted for by dietary or other relevant factors, and is interpreted as indicating increased tubular reabsorption of glutamine in primary gout. This interpretation was supported by the results of glutamine loading. The possible compensatory relationship of the abnormality in renal handling of glutamine to the deficiency in renal production of ammonia previously reported is discussed.