[Effects of arginine on properties of the erythrocyte membrane in hypoxia]. / Vliianie arginina na svoistva éritrotsitarnykh membran v usloviiakh gipoksii.

The antioxidant effect of arginine evident from stabilization of membrane structure and properties and activation of oxygen-toxicity-protecting enzymes was demonstrated in hypoxia. The intraperitoneal injection of L-arginine-HCl in a dose of 120 mg per 100 g body mass prevented the increase of microviscosity, membrane permeability and lipid peroxidation products level in hypoxia. At the same time the activity of the antioxidant enzymes--superoxide dismutase and catalase--was increased in red blood cells by 64 and 46%, respectively.

[Cytochrome P-450 activity and lipid peroxidation in rat liver and lung microsomes during hypoxia and followed by pressure oxygenation]. / Aktivnost' tsitokhroma P-450 i perekisnogo okisleniia lipidov v mikrosomakh pecheni i legkikh krys v usloviiakh gipoksii i posleduiushchei barooksigenatsii.

Influence of hypoxia (0.029 MPa, I h) followed by hyperoxia (0.2 MPa, I h) on microsomal oxidation and lipoperoxidation was studied in rat liver and lungs. Distinct increase of cytochrome P-450 catalytic activity with amidopyrine and benzo-a-pyrene as substrates of the I type was found after hypoxia, subsequent hyperoxia resulted in significant increase of amidopyrine and benzo-a-pyrene metabolism in liver and lung tissues and of aniline metabolism in liver tissue. Both hypoxia and hyperoxia led to increase in content of diene conjugates and Schiff bases in liver and lungs, while the increase of diene conjugates in liver and both diene conjugates and Schiff bases in lungs were observed under hyperoxic conditions.

[Regulation of by arginine of cytochrome p-450 activity and lipid peroxidation in rat liver and testicular tissue during hypoxia]. / Reguliatsiia argininom aktivnosti tsitokhroma P-450 i perekisnogo okisleniia lipidov v pecheni i semennikakh krys pri gipoksii.

Arginine, preadministered intraperitoneally at a dose of 120 mg per 100 g of body mass before hypoxia, decreased content of diene conjugates by 42-64% and Schiff bases by 7-15% in rat liver and testicular microsomal membranes as compared with control rats nontreated with arginine. Under these conditions cytochrome P-450 catalytic activity with aniline as a substrate was increased by 65-152% and with amidopyrine as a substrate--by 72-148%, respectively. Exogenous arginine inhibited an increase in membranes microviscosity, specific for hypoxic state; relative microviscosity of lipid bilayer was decreased by 36% and of the protein-lipid contact zones--by 84% as compared with control hypoxic animals.

[The cytochrome P-450 content and catalytic activity in rat liver microsomes during hyperbaric oxygenation]. / Soderzhanie i kataliticheskaia aktivnost' tsitokhroma P-450 v mikrosomakh pecheni krys pri giperbaricheskoi oksigenatsii.

The effect of different conditions of hyperbaric oxygenation (HBO) on content and catalytic activity of cytochrome P-450 in rat liver cytochrome has been studied. The intensity of lipid peroxidation in microsomal membranes has been determined by the content of dien conjugates and Schiff's bases. The rate of amidopyrine demethylation has been shown not to change, but the rate of aniline hydroxylation decreases on 34, 57 and 64% under increase of oxygen pressure up to 0.3, 0.5 and 0.7 MPa correspondingly. The level of dien conjugates increase on 66-87% under all studied conditions of HBO. Cytochrome P-450 content decreases on 45% under the action of 0.7 MPa, but content of Schiff's bases increases on 210% as compared with control.

[The effect of arginine on cytochrome P-450 activity and the structural state of the microsomal membranes of the rat liver and testes]. / Vliianie arginina na aktivnost' tsitokhroma P-450 i strukturnoe sostoianie membran mikrosom pecheni i semennikov krys.

A single intraperitoneal arginine injection increases the amidopyrin demethylation on 230% and aniline hydroxylation on 74% in rat liver microsomes. For all this the rate of lipid peroxidation estimated by the number of dienic conjugates and Schiff bases does not change. At the same time the exogenous arginine decreases the lipid bilayer microviscosity on 35% and increases the degree of protein submersion into lipid matrix on 54%. The experiments in vitro confirm the fact of activation in cytochrome P-450 isoform by arginine. A possible arginine effect on microsome membrane is under discussion.

[Antiradical and antioxidant effect of arginine and its action on lipid peroxidation in hypoxia]. / Antiradikal'nyi i antioksidantnyi éffekt arginina i ego vliianie na aktivnost' perekisnogo okisleniia lipidov pri gipoksii.

Arginine (0.5 and 1 mu mol) decreased by 14-17% rates of superoxide anion formation in two systems: HADH-phenazine methosulfate and hydroxylamine autooxidation with nitrotetrazolium blue. These concentrations of arginine decreased by 40-50% formation of diene conjugates and Schiff bases in plasma when lipid peroxidation initiated by iron -ascorbate. Arginine administration before hypoxia decreased lipid peroxidation rate in plasma and liver microsomal membranes of rats.

[A system of liver microsomal oxidation in hypoxia and hyperoxia]. / Sistema mikrosomal'nogo okisleniia pecheni pri gipoksii i giperoksii.

Content and catalytic activity of cytochrome P-450 were studied using amidopyrine as a substrate of the I type and aniline as a substrate of the II type. In hypoxia content of cytochrome P-450 and metabolism of amidopyrine were increased, while the enzyme content and the substrate metabolism were decreased in hyperoxia.

[Effect of arginine and its analogs on the activity of lysosomal and nonlysosomal peptide hydrolases in rat tissues]. / Vliianie arginina i analogov na aktivnost' lizosomal'nykh i nelizosomal'nykh peptid-gidrolaz v tkaniakh krys.

The autolysis intensity and proteolysis activity at pH 4,5, 7,4, 8,5 and lysosomal and nonlysosomal peptide hydrolase activity have been studied in brain and liver tissues of rats. L-arginine has been found to increase the peptide hydrolase activity in neutral and alkaline media in case of autolysis and proteolysis estimation according to the amino nitrogen increase. When the peptide hydrolase activity is estimated according to the increase of folin-positive components its decrease under the action of arginine in neutral and alkaline media has been revealed. Arginine doesn't change the lysosomal peptide hydrolase activity. In both tissues under the influence of arginine the nonlysosomal peptide hydrolase activity defined by amino nitrogen increases, estimated by the folin-positive components--decreases. Arginine shows the specific influence on the nonlysosomal peptide hydrolase activity. The L-arginine analogues (D-arginine, guanidine) and products of the arginase reaction (ornithine and urea) don't exert such an effect on the nonlysosomal proteolysis.

[Biochemical indices of the differentiation of cold stress and adaptation]. / Biokhimicheskie pokazateli differentsirovki kholodovogo stressa i adaptatsii.

Monoamine oxidase, acid peptide-hydrolase activities, intensity of lipid peroxidation in brain and liver tissues, hemoglobin content in blood serum, total peroxidase activity and glucose-6-phosphate dehydrogenase activity were investigated during the cold acclimation within 1-45 days, 4 degrees. Cold stress within 1-3 days destabilized erythrocyte, lysosomal and mitochondrial membranes in the rat tissues studied. At the same time, cold adaptation within 45 days prevented the membrane labilization.

[Effect of arginine on the activity of proteolytic enzymes in the rat brain and liver]. / Vliianie arginina na aktivnost' proteoliticheskikh fermentov v mozgu i pecheni krys.

The influence of arginine on autolysis and proteolysis was studied. Arginine at the concentration of 0.5 and 1.0 microM/ml was added to the incubation mixture. Proteolytic processes were studied in the acid, neutral and alkaline media (pH 4.5; 7.4; 8.5). Autolysis was determined by incubation of the brain and liver homogenates and proteolysis by the use of bovine serum albumin as a substrate. Autolytic and proteolytic activities were calculated as an increase of Folin positive compounds or amino nitrogen in the samples. It was established that the influence in vitro of arginine on the proteolytic processes depended on pH, type of the peptide-hydrolases, to a lesser extent, on the arginine concentration and did not depend on the tissue type. Arginine displayed its regulative action in the brain and liver by the same way. The addition of arginine had an effect on autolysis and proteolysis in the neutral and alkaline media. Determination of autolytic and proteolytic activities by Folin positive compounds has shown that arginine addition into the samples decreased autolysis and proteolysis. At the same time determination of autolysis and proteolysis by amino nitrogen in the presence of arginine has shown that autolytic and proteolytic activities increased.

[Biochemical indices of the sensitivity of cold-adapted animals to hyperoxic exposure]. / Biokhimicheskie pokazateli chuvstvitel'nosti adaptirovannykh k kholodu zhivotnykh k deistviiu giperoksii.

It has been established that white rats adapted to the low temperature of the environment (45 days 2-4 degrees C) in contrast to the animals undergoing such action during 3 days (cold stress) show resistance to the toxic action of the high oxygen pressure. The considerable removal of convulsions under the action of oxygen, the absence of increase of erythrocyte membrane permeability in the preconvulsive stage of hyperoxia and prevention of changes in the substrate specificity of type A monoamine oxidase both in preconvulsive and convulsive periods of oxygen intoxication are their characteristics.

[Monoamine oxidase activity and gamma-aminobutyric acid levels in hyperoxia. The effect of clorgyline]. / Aktivnost' monoaminoksidazy i uroven' gamma-aminomaslianoi kisloty pri giperoksii. Vliianie khlorgilina.

Under conditions of hyperoxia mitochondrial monoamine oxidase (MAO) of the A type from rat brain proved to be able to deaminate gamma-aminobutyric acid (GABA); the transformation in the enzymatic properties appears to be responsible for a decrease in content of the intermediator in brain. Preadministration of chlorgiline (inhibitor of MAO of the A type) into animals before hyperoxygenation prevented completely the GABA content decrease, not affecting the glutamate decarboxylase activity, which was decreased in hyperoxia. At the same time, chlorgiline exhibited the total protective effect increasing 2-fold the period before oxygen convulsions.

[Evaluation of the effectiveness of the protective effect of arginine in cold stress]. / Otsenka éffektivnosti zashchitnogo deistviia arginina v usloviiakh kholodovogo stressa.

Cold exposition within 3 days at 2-4 degrees caused destabilization of rat erythrocyte membranes. Content of blood serum hemoglobin, total peroxidase activity and the glucose-6-phosphate dehydrogenase activity were increased. Resistance of the animals against high oxygen pressure was reduced. Administration of arginine within 3 days into the animals led to stabilization of membranes and to elevation of rat resistance towards high oxygen pressure.

[Effect of arginine on the arginase activity and urea content of the brain and liver of rats acclimating to cold]. / Vliianie arginina na aktivnost' arginazy i soderzhanie mocheviny v mozge i pecheni krys pri akklimatizatsii k kholodu.

At cold stress (3 days exposition at 2--4 degrees C) the urea formation in rats brain and liver does not become more active, the content of extraerythrocytic hemoglobin and the total peroxydase activity increase in blood serum, the animals sensitivity to the action of hyperbaric oxygenation (HB0) grows. At cold adaptation (45 days at 2--4 degrees C) the urea content in tissues and the activity of arginase in liver increase, the concentration of extraerythrocytic hemoglobin and the total peroxydase activity normalize, animals become more resistant to HB0. Every day administration of arginine during 3-day cold effect makes the brain and liver arginase on 42 and 28% more active, increases the urea content on 26 and 19%, stabilizes the erythrocytic membranes. The animals protected by arginine against cold are more resistant to the action of HB0.

[Glucose-6-phosphate dehydrogenase activity in rat serum in hyperoxia, hypoxia, and cooling]. / Aktivnost' gliukozo-6-fosfatdegidrogenazy v syvorotke krovi krys pri giperoksii, gipoksii i kholodovom vozdeistvii.

Activity of glucose-6-phosphate dehydrogenase (G6PD) was increased in blood serum in hypoxic hypoxia, hypoxia and cooling stress. The degree of this alteration depended on duration of the action of the effectors and on oxygen pressure. Adaptation to cooling was characterized by stabilization of enzymatic activity at the new metabolic step. Mechanisms of G6PD activation in blood serum under conditions of extreme states as well as the possibilities of utilization of this phenomenon as a test are discussed.

[Polyamine contents in the brain and liver of rats during acclimatization to the cold]. / Soderzhanie poliaminov v mozgu i pecheni krys v protsesse akklimatsii k kholodu.

The content of polyamines, spermidine and spermine in the brain and liver was studied in rats during acclimation to cold for 45 days. In the brain the amount of spermidine after one and three days does not change, on the 7th and 15th day it decreases and by the end of acclimation returns to the control value. The content of spermine lowers by 29% by the third day of acclimation and on the 7th day returns to the initial level and does not change up to it end. In the liver the amount of spermidine rises significantly on the third day of acclimation, returns to the control level on the 7th day and then its amount falls. The content of spermine is increased in all period of acclimation and only by the 45th day it returns to its initial level.

[Mechanisms of the effect of cold adaptation on the resistance to hyperoxia]. / O mekhanizmakh vliianiia adaptatsii k kholodu na ustoichivost' organizma k giperoksii.

Hyperoxia after 3-day exposure at 2-4 degrees C induces more obvious disturbance of metabolites in rats than each of the factors separately. Along with decreased arginase activity in the brain and liver by 23 and 32% resp., the urine content decreases as well by 36 and 37% resp. Resistance of these animals against hyperoxia is reduced. But a preliminary 45-day cold-adaptation at 2-4 degrees C leads to a considerable activation of liver arginase and to increased content of urine in brain and liver by 32 and 30%, resp. The activation of arginase--urine system preserves under hyperoxia: the cold-adapted animals prove more resistant against hyperoxia effect. The above dynamic changes seem to be one of possible unspecific biochemical mechanisms of increasing the organism resistance against effects of extreme factors.

[Polyamines and activity of acid peptide-hydrolases in hyperoxia]. / Poliaminy i aktivnost' kislykh peptidgidrolaz pri giperoksii.

The content of spermidine and spermine polyamines in the rat brain under hyperoxic convulsions and four hours after convulsions decreases sharply. The intraperitoneal administration of polyamines before hyperbaric oxygenation decreased the rate of development of hyperoxic convulsions in rats. In the model experiments polyamines prevented changes in the acid peptide-hydrolase activity in the lysosomal and soluble fractions, which occur under hyperoxia.

[Activity of arginase and proteolytic processes in the brain and liver of rats in cold acclimatization]. / Aktivonst' arginazy i proteoliticheskie protsessy v mozge i pecheni krys v khode akklimatsii k kholodu.

The activity of arginase, neutral peptidohydrolase (protaminase) and total intensity of autolysis were determined in the brain and liver of rats on the 1st, 3d, 30th and 45th days animal stay at a temperature of 2-4 degrees C. in the process of rats acclimatization to cold there occurs a correlation in the brain - between the activity of arginase and neutral peptidohydrolase, in the liver - between the arginase activity and total proteolytical activity (autolysis).

[Cerebral and hepatic arginase and polyamines in the mechanisms of the protective effect of arginine in hyperoxia]. / Arginaza i poliaminy mozga i pecheni v mekhanizme zashchitnogo deistviia arginina pri giperoksii.

The effect of protective concentrations of arginine on the arginase activity and the content of rat brain and liver spermidine and spermine was studied under hyperoxia (6 atmospheres). Intraperitoneal injection of arginine to intact animals increases the arginase activity and the brain content of spermidine and spermine by 15, 19 and 25%, respectively. The liver arginase activity rises by 55%, while the level of the polyamines remains almost unchanged. Arginine injection before hyperoxic exposure prevents the significant lowering of the arginase activity and polyamine content seen in the unprotected animals. The relationship between the arginase activity and the polyamine level in the brain and liver is discussed with emphasis on arginine efficacy as protective agent in hyperoxia.