[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.

[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.

[Catabolism of pyrimidine nucleotides in the liver of irradiated animals]. / Issledovanie katabolizma pirimidinovykh nukleotidov v pecheni obluchennykh zhivotnykh.

A study was made of the activity of nucleoside diphosphatase (NDPase, EC 3.6.1.16) and nucleoside triphosphatase (NTPase, EC 3.6.1.15) that catalyze enzymatic dephosphorylation of UDP, CDP, UTP, and CTP in mitochondria and postmitochondrial supernatant fraction of rat liver 30 min, 1, 3, 6 and 24 h following 60Co-gamma-irradiation with a dose of 774 mC/kg. The observed phase changes in the enzyme activity depended on the times of exposure, a cell fraction, and nucleotides under study. Both uridylic and cytidylic nucleotides exhibited a significant increase in the their enzymatic disintegration being more pronounced at a comparatively later times, that is, 6 h, and particularly, 24 h after irradiation.

[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.

[Adenylate kinase isoenzymes in rat liver and blood serum in radiation sickness]. / Izofermenty adenilatkinazy pecheni i syvorotki krovi krys pri luchevoi bolezni.

A study was made of isoenzyme activity of adenylate kinase of rat liver and blood serum 3, 7 and 15 days following whole-body X-irradiation in a dose of 154.8 mC/kg. A considerable increase was noted in activity of isoenzyme II in mitochondria, and isoenzyme I in the liver supernatant fraction. Out of three isoenzymes of blood serum isoenzyme I was most changeable in activity.

[5-nucleotidase activity in rat leukocytes, erythrocytes and blood serum during radiation sickness]. / Aktivnost' 5-nukleotidazy v leikotsitakh, éritrotsitakh i syvorotke krovi krys pri luchevoi bolezni.

A study of 5-nucleotidase activity in the formed elements and blood serum of rats 1, 3, 7, 15 and 30 days after X-irradiation has demonstrated that it was increased in leukocytes at early times and inhibited at later times of the development of radiation sickness. In erythrocytes, inhibition of 5-nucleotidase activity was most pronounced on the 3d day. In blood serum, the enzyme activity was virtually invariable. The addition of ATP to the incubation medium normalized 5-nucleotidase activity.

[Adenylate kinase activity of the blood of irradiated rats]. / Aktivnost' adenilatkinazy v krovi obluchennykh krys.

The direct and reverse adenylate kinase reactions were studied in blood of rats 1, 3, 7, 15 and 30 days after total X-ray irradiation with a dose of 154.8 mC/kg (600 R) dose. It is found out that adenylate kinase (CE 2.7.4.3) activity in leucocytes and erythrocytes is inhibited on the 3d, 7th and 15th days of the study. Inhibition of the reverse adenylate kinase reaction is pronounced to a greater extent than that of the direct one. The adenylate kinase of erythrocytes is more stable to the effect of ionizing radiations as compared to this enzyme of leucocytes. When the enzymic activity in the blood cells is inhibited, the activity of the direct adenylate kinase reaction in the serum increases significantly and that of the reverse one remains unchanged.