[Monoamine oxidase activity in gastrointestinal tract tissues of animals after irradiation and administration of pyridoxal phosphate]. / Monoaminoksidaznaia aktivnost' tkanei zheludochno-kishechnogo trakta zhivotnykh posle oblucheniia i vvedeniia piridoksal'fosfata.

The X-ray irradiation in a dose of 450 R is shown to decrease the monoaminoxidase activity in the cell fractions of the mucous membrane of small intestine as against the fractions of the stomach mucosa. The administration of pyridoxalphosphate to the irradiated rabbits increases the monoaminoxidase activity in the fraction and subfractions of small intestine mucosa mitochondria, but the enzyme activity being compared with the control group has a tendency to decrease.

[Increase in 5'-nucleotidase and decrease in guanylate kinase activity in the brain and liver of irradiated rats]. / Povyshenie aktivnosti 5'-nukleotidazy i snizhenie guanilatkinazy v golovnom mozge i pecheni obluchennykh krys.

The activity of 5-nucleotidase (EC 3.1.3.5) and guanylate kinase (EC 2.7.4.8) in the mitochondria and supernatant of the brain and liver was determined in experiments on Wistar male rats 1, 3, 6, 24 and 48 h after the single total irradiation by gamma-quanta in a dose of 30 Gy. It is established that the activity of 5-nucleotidase in the liver endures phase changes with the predominance of the enzyme activation; in the brain it is higher during the whole period of investigation. The guanylate kinase activity lowers in the both fractions of the organs under study during the whole period of the experiment.

[Changes in the brain GABA system after repeated injections of pyridoxal-5'-phosphate and its Schiff base with GABA]. / Izmeneniia v sisteme GAMK golovnogo mozga pri mnogokratnom in''etsirovanii piridoksal'-5'-fosfata i ego shiffova osnovaniia s GAMK.

A state of the gamma-aminobutyric acid (GABA) system (glutamate, glutamate decarboxylase, GABA, GABA-alpha-ketoglutarate aminotransferase) and the coupled reactions (alpha-ketoglutarate dehydrogenase complex, aspartate- and alanine aminotransferases) was studied in three brain structures (cerebellum, brain cortex and truncus cerebri) after multiple administration of pyridoxal-5'-phosphate (PALP) and its Shiff base with GABA (5 injections at doses 10.0 and 15.0 mg/kg of body mass, respectively). Non-coenzymatic effects of PALP were found to prevail within 1 hr after its last administration: inhibition of PALP-dependent aminotransferases and activation of the alpha-keto-glutarate oxidative decarboxylation were observed. The opposite effects were detected after addition of PALP to brain homogenates in vitro. Administration of the PALP-GABA complex exhibited qualitatively similar to those of PALP effects on the reactions studied in brain. The data obtained suggest that parenteral administration of the coenzyme preparation caused a number of metabolic effects, which are sometimes far from unambigously predicted theoretical considerations. The similarity of PALP and PALP-GABA effects appears to demonstrate ready biotransformation of the Shiff base with liberation of PALP and GABA.

[Changes in the level of pyrimidine nucleoside phosphates in the liver of irradiated rats]. / Izmeneniia soderzhaniia pirimidinovykh nukleozidfosfatov v pecheni obluchennykh krys.

Content of uridyl and cytidyl nucleoside-phosphates in the liver of rats irradiated by gamma-rays (60Co) in a dose of 774 mC/kg (3000 P) was studied 0.5, 1, 3, 6 and 24 h after the effect. A trustworthy decrease of UTP and CTP as well as UDP and CDP content 24 h after irradiation was found. The number of pyrimidine nucleoside monophosphates increases after 24 h of the effect.

[Mitochondrial monoamine oxidase activity and serotonin content of rat brain following gamma-irradiation]. / Issledovanie aktivnosti mitokhondrial'noi monoaminoksidazy i soderzhaniia serotonina v golovnom mozge krys posle vozdeistviia gamma-izlucheniia.

It is shown that gamma-irradiation of albino rats with a dose of 30 Gy leads to pronounced phase changes in monoaminoxidase activity and serotonin content in rat brain at early times after whole-body exposure. There is a similar direction of changes in the activity of the enzyme and in the content of the substrate adequate to the latter.

[Changes in fructosediphosphate aldolase and glucose-6-phosphate dehydrogenase activity after irradiation of animals with an absolute lethal dose of gamma rays]. / Izmenenie aktivnosti al'dolazy fruktozodifosfata i gliukozo-6-fosfatdegidrogenazy pri obluchenii zhivotnykh gamma-luchami v absoliutno letal'noi doze.

A single total-body exposure of rats to gamma-rays in an absolutely lethal dose caused significant changes in the activity of fructosodiphosphate aldolase (ALD) and glucose-6-phosphate dehydrogenase (G-6-PDH) in the brain, liver, myocardium and skeletal muscles. The activity of ALD was mainly inhibited and that of G-6-PDH increased. Thus, the initial step of glycolysis was significantly inhibited and the key reaction of the pentose phosphate pathway enhanced in the irradiated body.

[Change in the ornithine carbamoyltransferase activity in rats following roentgen irradiation and administration of a vitamin-coenzyme complex]. / Izmenenie aktivnosti ornitinkarbamoiltransferazy u krys posle rentgenovskogo oblucheniia i vvedeniia vitaminokofermentnogo kompleksa.

A whole-body X-irradiation (5.82 Gy) increases the activity of ornithine carbamoyl transferase (OCT) on days 3, 7, 15 and 60. After the administration of a complex of vitamins and coenzymes on days 7, 15 and 60 OCT activity decreased as compared to that of untreated animals. A correlation was noted between the activity of OCT in the liver and blood serum.

[Role of adenylate kinase, AMP deaminase and 5'-nucleotidase in the metabolism of adenylic nucleotides]. / Rol' adenilatkinazy, AMP-dezaminazy i 5'-nukleotidazy v metabolizme adenilovykh nukleotidov.

The activities of adenylate kinase, AMP-deaminase and 5'-nucleotidase in various tissues of the rat were studied. The activity of the forward adenylate kinase reaction (ATP + AMP----2 ADP) against the back one (2 ADP----ATP + AMP) was predominant. The liver was shown to contain two, while the blood serum--three adenylate kinase isoenzymes. In the skeletal muscles, the catabolism of adenylic acid involving AMP-deaminase and 5'-nucleotidase predominantly occurred via deamination, in the liver--via dephosphorylation, while in the leucocytes, erythrocytes and blood serum the activity of these processes was essentially the same. In vitro, ATP enhanced the activity of AMP-deaminase in the liver, leucocytes and erythrocytes and decreased it in the blood serum. Under effects of ATP, the activity of 5'-nucleotidase in the leucocytes and blood serum was markedly elevated, that in the liver and erythrocytes was unaffected.

[Nucleoside mono- and nucleoside diphosphate kinase activities in rat liver and brain in radiation sickness]. / Nukleozidmono- i nukleoziddifosfatkinaznaia aktivnost' pecheni i golovnogo mozga krys pri luchevoi bolezni.

Activity of nucleoside di- and nucleoside triphosphates metabolism enzymes in tissues of rats gamma-irradiated by a dose of 30 Gy was studied 0.5, 1, 3, 6 and 24 hours after the radiation effect. It is shown that the nucleoside monophosphate kinase activity of the liver and brain is enhanced almost at all stages of the studies and the nucleoside diphosphate kinase activity is inhibited. A significant but reversible decrease of the nucleoside monophosphate kinase activity is observed in the liver 3 h later. By an end of the first day after irradiation the nucleoside mono- and nucleoside diphosphate kinase activities increase significantly both in the liver and brain.

[Early changes in the nucleoside diphosphate kinase activity of the rat brain and liver during whole body gamma irradiation in an absolutely lethal dose]. / Rannie izmeneniia nukleoziddifosfatkinaznoi aktivnosti golovnogo mozga i pecheni krys pri obshchem gamma-obluchenii v absoliutno letal'noi doze.

Nucleoside diphosphatkinase activity in mitochondria and post-mitochondrial supernatant fraction from brain and liver tissues was shown to decrease sharply during the first 60 min after total-body gamma-irradiation of rats with an absolutely lethal dose (30 Gy). A significant increase in the enzyme activity was registered 3 and 24 h following irradiation. Changes in nucleoside diphosphatkinase activity were more pronounced in mitochondria (particularly in liver mitochondria) than in the supernatant fraction.

[Changes in the transaldolase activity in the liver, spleen and bone marrow of rats after total X-ray irradiation]. / Izmenenie aktvnosti transal'dolazy v pecheni, selezenke i kostnom mozge krys posle total'nogo rentgenovskogo oblucheniia.

The paper deals with changes in the activity of transaldolase in tissues of the liver, spleen and bone marrow of rats 4.24 h and on the 3 d, 7th, 18th, 30th, 45th, and 60th day after total X-ray irradiation in a dose of 600 R. The ionizing irradiation causes a stable inhibition of the enzyme activity in All tissues. The observed changes are homogeneous in their direction but have their own peculiarities for each tissue. Differences in the degree and extent of the enzyme activity changes at various stages of the X-ray lesion development in the tissues under study may be explained by their different sensitivity to the penetrating radiation.