[Effect of pyrazole on the activity of acetaldehyde-producing enzymes in the liver]. / Vliianie pirazola na aktivnost' atsetal'degidprodutsiruiushchikh fermentov pecheni.

Influence of pyrazole on the endogenous ethanol level and activities of acetaldehyde-producing enzymes was investigated. Drastic enhancement of the endogenous ethanol level in the blood and tissues was accompanied by an insignificant increase of phosphoethanolamine lyase activity, while activity of threonine aldolase and pyruvate dehydrogenase was unchanged.

[Lipid fractions of rat liver upon administration of ethanol and ethanolamine]. / Lipidnye fraktsii pecheni krys ri vvedenii étanola i étanolamina]

After a single intragastric administration of 25% ethanol in a dose of 1 g/kg of body mass content of total lipids, lysophosphatidyl choline, phosphatidyl ethanolamine and cardiolipin was increased while phosphatidyl choline was decreased in the rat liver tissue. At the same time, there was a decrease in the rate of 2- 14C-acetate incorporation into esters of cholesterol, total phospholipids, lysophosphatidyl choline, sphingomyelin, phosphatidyl ethanolamine and cardiolipin. Administration of ethanolamine simultaneously with ethanol contributed to normalization of the lipid spectrum, impaired by the single ethanol inoculation.

[Diagnostic effectiveness of determining the activity of certain serum enzymes in alcoholism patients]. / Diagnosticheskaia éffektivnost' opredeleniia aktivnosti nekotorykh syvorotochnykh fermentov u bol'nykh alkogolizmom.

Activities of alcohol, aldehyde dehydrogenases (ADH, A1DH, respectively) and gamma-glutamyl transferase (GGT) were estimated in blood serum of patients with Stages I-III alcoholism (54 men) on admission to the hospital, within 1 hr after ethanol testing (in a dose of 0.4 g/kg of body mass) and during the treatment course. Distinct activation of ADH and GGT and decrease in activity of A1DH were found in the patients as compared with healthy volunteers. Alcohol test did not alter noticeably the enzymatic activity studied. The activity of ADH and GGT was normalized in patients with Stages I-II alcoholism during the treatment course. A1DH exhibited the highest diagnostic efficacy, whose sensitivity and specificity were 92% and 84%, respectively; those for ADH 74% and 86% and for GGT 44% and 90%, respectively. Simultaneous estimation of the activity of the three enzymes improved the sensitivity and efficacy of diagnostic technique and enabled the test to be used as an additional criterion in the diagnosis of alcoholism and in the evaluation of the patients' state and therapeutical efficacy.

[Coenzyme-binding sites of the brain pyruvate dehydrogenase complex]. / Izuchenie kofermentsviazyvaiushchikh tsentrov piruvatdegidrogenaznogo kompleksa mozga.

It is shown that the relative amount of the holoenzyme in the highly purified pyruvate dehydrogenase complex from the bovine brain is higher when the enzyme activity is assayed in the reaction of nonoxidative formation of acetaldehyde as compared to the pyruvate: NAD+ reductase reaction. The S0.5 values for thiamine pyrophosphate are as following: (TPP) (0.314 +/- 0.22) x 10(-7) M with reaction of nonoxidative formation of acetaldehyde, (0.188 +/- 0.08) x 10(-6) M and (1.65 +/- 1.16) x 10(-6) M in case of the pyruvate: NAD+ reductase reaction. TPP in the concentration of (0.5-6.0) x 10(-7) M completely protects the sites of nonoxidative formation of acetaldehyde from modification by the coenzyme analogs, 4'-oxythiamine pyrophosphate and tetrahydrothiamine pyrophosphate. However, the pyruvate: NAD+ reductase activity of the pyruvate dehydrogenase complex is inhibited in this case by 30-34%. The data obtained suggest that in contrast to the pyruvate: NAD+ reductase reaction the conversion of pyruvate to acetaldehyde occurs by the sites which tightly bound TPP.

[Features of thiamine diphosphate-dependent enzyme inhibition by oxodihydrothiochrome and its phosphorylated derivatives]. / Osobennosti ingibirovaniia tiamindifosfatzavisimykh fermentov oksodigidrotiokhromom i ego fosforilirovannymi proizvodnymi.

Anticoenzyme action of new derivatives of thiamine: oxodihydrothiochrome and its mono- and diphosphoric esters has been studied in the experiments on mice. It is shown that the given compounds exert an inhibiting action on transketolase and pyruvate dehydrogenase and do not change activity of 2-oxoglutarate dehydrogenase in the animal organism. Antivitamin effect of the studied inhibitors is observed with the lower doses and in the earlier terms as compared with the other known inhibitors of thiamine-diphosphate-dependent enzymes. The preparations inhibit activity of the yeast pyruvate-decarboxylase by the mixed (with respect to thiamine-diphosphate) type (Ki for oxodihydrothiochrome and its mono- and diphosphoric esters: 2.3 x 10(-3), 7.2 x 10(-4), 5.6 x 10(-5) M, respectively). Possible mechanisms of the action of the mentioned compounds as thiamine antimetabolites are discussed.

[The effect of phosphorylation on oxidative and CoA- and NAD+-independent turnover of pyruvate by pyruvate dehydrogenase complex in the brain]. / Vliianie fosforilirovaniia na okislitel'noe i CoA- i NAD+- nezavisimoe prevrashchenie piruvata piruvatdegidrogenzanym kompleksom mozga.

It was shown that in the presence of ATP and Mg2+ the phosphorylation of the partially purified pyruvate dehydrogenase complex and the enzyme in isolated brain mitochondria inhibited the oxidative activity of the pyruvate dehydrogenase complex. The phosphorylation did no affect essentially the nonoxidative decarboxylation of pyruvate to form CO2 and acetaldehyde. In native mitochondria from the bovine brain the nonoxidative activity of the pyruvate dehydrogenase complex reached about 10% as compared to the oxidative activity of enzyme.

[Formation of free fatty acid pool in the liver of rats during starvation]. / Formirovanie fonda svobodnykh aminokislot pecheni krys v dinamike golodaniia.

Absolute starvation during 2 days induces increased levels of taurine, phosphoethanolamine, ethanolamine, glycine, serine, threonine and decreased levels of aspartate, lysine, methionine and cystine in the rat liver. The ration of nonessential to essential, and glycogenic to ketogenic amino acids increased on the average by 30%. On day 4 of starvation the level of nonessential glycogenic amino acids is significantly lowered, while the concentration of essential ketogenic amino acids is increased. On day 6 essential ketogenic amino acid pool is more increased. On day 10 the shifts in the amino acid pool in the liver are retained, the reduction of alanine and serine content is most typical. The value of D2-Machalanobis, obtained during lineal discriminant analysis of amino acid pool and space distribution of the signs for the control and starving animals (during 10 days), was lower than that on day 4 and 6 of the experiment. The levels of glycine, serine lysine, leucine, glutamate, alanine and aspartate show the highest information content during such investigation of all the groups of animals.

[Optimization of hydroxythiamine administration regimen in vitaminological research]. / Optimizatsiia rezhima ispol'zovaniia oksitiamina v vitaminologicheskikh issledovaniiakh.

A correlation between the different doses and inhibitory effect of hydroxythiamine relative to the activity of main thiamine pyrophosphate-dependent enzymes is studied in experiments on animals. It is established that the maximal inhibitory effect on the transketolase and oxoglutarate dehydrogenase activities is at a dose of antivitamin of 0.35 mmol/kg and that of pyruvate dehydrogenase of 0.55 mmol/kg. At lower doses of hydroxythiamine the inhibition of enzyme activities occurred in a dose-dependent manner.

[The effect of disulfiram on lipid metabolism in the rat liver]. / Vliianie disul'firama na metabolizm lipidov v pecheni krys.

Administration of disulfiram (200 mg/kg intragastrically for 3 days) was followed by an increase in the rat liver contents of total phospholipid fraction, triacylglycerine, lisophosphatidylcholine and a decrease in the relative level of phosphatidylethanolamine. This was associated with a decrease in the involvement of the tracer from 14C-ethanol in triacylglycerines, total phospholipids, lisophosphatidylcholine and cardiolipin. Alcohol injection (a 20% solution intraperitoneally in a dose of 1 g/kg for 30 minutes) against the background of treatment with disulfiram leads, in addition to the above-mentioned changes, to an increase of phosphatidylcholine concentration, a decrease of specific radioactivities of cholesterol, diacylglycerine and sphyngomyelin.

[Endogenous ethanol in the blood and tissues of rats with hypobaric hypoxia]. / Endogennyi étanol krovi i tkanei krys pri gipobaricheskoi gipoksii.

Albino male rats weighing 160-180 g were used to study the effect of short-term hypobaric hypoxia (ascent in an altitude chamber to 2500 m and 5000 m for 1 hr) on endogenous ethanol measured in blood, brain and liver; simultaneously enzymes responsible for ethanol and acetaldehyde metabolism were determined. Endogenous ethanol in blood and tissues was found to be a very sensitive marker of hypoxia which was not correlated with lactate, pyruvate, lipid peroxidation or 11-hydroxycorticosteroids. The latter parameters varied in response to severe hypoxia.

[Formation of taurine and amino acid pools in rat tissues upon stimulation of NAD synthesis]. / Formirovanie taurinovogo pula i aminokislotnogo fonda v tkaniakh krys v usloviiakh stimuliatsii sinteza NAD.

A single intraperitoneal injection of nicotinamide (500 mg/kg) to mongrel albino rats causes a 6-hour increase in the 2-oxoglutarate level and the free NAD+/NADH ratio in liver mitochondria. The levels of taurine and taurocholates as well the activity of cysteine oxidase in liver tissues remains thereby unchanged, whereas the cysteine transaminase activity diminishes. In the heart and brain of experimental animals the activity of both enzymes is decreased. In the liver, blood plasma and heart of experimental animals, the Ala and Ser levels are low, whereas the taurine content is elevated both in blood plasma and brain. Nicotinamide administration eliminates positive correlations between the levels of taurine, its precursors and metabolically bound amino acids. In the liver the negative correlations between the activities of cysteine oxidase and cysteine transaminase observed in the control group disappear in the experimental group. Apparently, one of regulatory mechanisms of the taurine pool formation in the liver is the ratio of activities of the both enzymes as well as their competition at the substrate level. This emphasizes the importance of the transamination reactions in the metabolism of sulphur-containing amino acids.

[Effect of oxythiamine disulfides on the pancreas and thyroid of rats]. / Vliianie disul'fidov oksitiamina na podzheludochnuiu i shchitovidnuiu zhelezy krys.

Single administration of oxythiamine (200 mg/kg) or an isomolar amount of oxythiamineamyldisulfide to rats does not change the content of insulin in 72 h, whereas oxythiaminehexyldisulfide slightly increases the blood level of the hormone. Oxythiamine and its disulfides cause changes of the thyroid indicating considerable suppression of its function. It is assumed that hormonal mediation of oxythiamine nonspecific metabolic effects results predominantly from the involvement of the thyroid hormones rather than insulin.

[The action of nicotinamide on the adenine nucleotide system as well as on mitochondrial oxidation and phosphorylation processes in the liver of db/db strain mice]. / Deistvie nikotinamida na sistemu adeninovykh nukleotidov, a takzhe na protsessy mitokhondrial'nogo okisleniia i fosforilirovaniia v pecheni myshei linii db/db.

Both levels of total adenine nucleotides, ATP, AMP, ATP/ADP ratio and phosphate potential of cell and cytosol and the intensity of mitochondrial oxidation (fatty acid beta-oxidation in particular) and phosphorylation are elevated in the liver of db/db mice as compared with control. Presumably these alterations corresponding to the total activation of metabolic processes in db/db mice are mediated by hyperinsulinemia. Nicotinamide treatment (2.5 mg/100 g body weight, 14 days, i.m.) elicits further increase of ATP and total adenine nucleotide levels, cytosolic phosphate potential and activation of mitochondrial oxidation and phosphorylation. The findings obtained can be used for explanation of nicotinamide inhibition of gluconeogenesis, diacylglycerol and phosphoacylglycerol biosynthesis in the liver of db/db mice.

[Antivitamin activity of O-acyloxythiamine disulfides]. / Antivitaminnaia aktivnost' O-atsiloksitiamindisul'fidov.

B1-antivitamin activity of symmetrical oxythiamine disulphide esters with succinic and o-phthalic acids has been studied in experiments on albino mice. It is shown that O-acyloxythiamine disulphides exert more profound and prolonged inhibitory effect on the transketolase activity in the animal body in comparison with the known antagonist of vitamin B1, oxythiamine, and the initial oxythiamine disulphide.

[Effect of phosphopantothenate on the biosynthesis of cholesterol and its esters from various precursors in the liver of db/db mice]. / Deistvie fosfopantotenata na biosintez kholesterina i ego efirov iz razlichnykh predshestvennikov v pecheni myshei db/db.

It was found that in the livers of db/db mice with hyperinsulinemia, obesity and non-insulin-dependent diabetes the rates of cholesterol biosynthesis from pyruvate and, to a lesser extent, from acetate and mevalonate as well as of cholesterol ester biosynthesis from pyruvate (but not from acetate and mevalonate) are increased. Presumably, the observed changes are mediated by structural alterations in the CoA reserves, i.e., increase of free CoA to short-chain acyl-CoA and free CoA to long-chain fatty acyl-CoA indices, and of the ratio between enzymatic activities of generation and utilization of NADPH. Treatment of db/db mice with phosphopantothenate, besides eliciting changes in the CoA reserves structure towards normalization and inhibition of NADP-dependent dehydrogenases and pyruvate and 2-oxoglutarate dehydrogenase complexes, causes the diminution of cholesterol and its ester levels in the liver in the absence of any conspicuous changes in the rates of their biosynthesis from pyruvate.

[Optimization of a method of determination of endogenous ethanol in the blood and tissues of man and experimental animals]. / Optimizatsiia tekhniki opredeleniia urovnia éndogennogo étanola v krovi i tkaniakh cheloveka i éksperimental'nykh zhivotnykh.

An improved procedure is described for estimation of endogenous ethanol in human and animal biological fluids using gas chromatographic analysis of equilibrated steam. Sensitivity of the procedure was as low as 0.05 mg/L and relative error--about 6%. Content of endogenous ethanol constituted from 0.08 mg/L to 1.30 mg/l (the mean value was 0.38 +/- 0.07 mg/L) in blood of healthy men which did not consume alcohol for a long time. In blood and tissues of white rats content of ethanol was equal to 0.06-1.32 mg/L and 0.07-3.12 mg/l, respectively.

[The effect of chronic alcoholic intoxication on the level and metabolism of glycolipids in the rat brain]. / Vliianie khronicheskoi alkogol'noi intoksikatsii na soderzhanie i metabolizm glikolipidov v golovnom mozgu krys.

The chronic alcohol intoxication has been studied for its effect on the content of glycolipids in the rat brain and incorporation of [I-14C]acetate into them. It is established that administration of ethanol to animals (2 g per 1 kg of body weight daily for 7 days) rises the content of cerebrosides I in the brain tissue. The specific radioactivity of sulphatides I falls as a result of a decrease of the [I-14C]acetate into fatty acids and galactose. The specific radioactivity of sulphatides II, cerebrosides II and III falls as a result mainly of a decrease of the specific radioactivity in the galactose components.

[Aldehyde dehydrogenase activity in the barrier brain structures]. / Aktivnost' al'degiddegidrogenazy v bar'ernykh strukturakh mozga.

The histochemical method was used to study the aldehyde dehydrogenase (EC 1.2.1.3.; ALDH) activity in capillaries and glial structures of different regions in the rat central nervous system (CNS). The occurrence of three metabolic barriers for aldehydes on systemic level in the CNS has been shown. They are: the barrier between blood and the nervous tissue (represented by capillary endothelium and surrounding astrocytes ALDH), that between blood and cerebrospinal fluid (ALDH in ependymocytes of vascular plexus), and that between cerebrospinal fluid and nervous tissue (ALDH of ependymocytes covering brain cavities). On the single microregions level a similar barrier is between interstitial fluid and neurons (ALDH of satellite oligodendrocytes).

[Acetoin metabolism in animal tissues]. / Metabolizm atsetoina v zhivotnykh tkaniakh.

The acetoin-synthesizing activity has been studied in the skeletal muscles, brain, liver and spleen homogenates (numbered as the activity decreases). The acetoin-synthesizing activity drastically increases in case of the acetaldehyde excess and alcohol intoxication. The acetaldehyde concentrations of above 1.10(-3) M inhibit the liver pyruvate dehydrogenase activity and increase the non-oxidative transformation of pyruvate. Acetoin is rapidly metabolized in the organism eliminating from blood 10 minutes after its injection. Acetoin is an effective precursor in the biosynthesis of lipids.