[Effect of irradiation on the intensity of chromatin protein synthesis in the rat liver during protection with serotonin in pulsed inhibition of translation by cycloheximide]. / Vliianie oblucheniia na intensivnost' sinteza belkov khromatina v pecheni krys pri zashchite serotoninom v usloviiakh impul'snogo tormozheniia transliatsii tsiklogeksimidom.

The model of impulse translation inhibition by cycloheximide in the rat liver was used for studying the combined and separate effect of serotonin and irradiation on the intensity of synthesis of chromatin proteins (histones and nonhistone proteins). Irradiation induces a considerable inhibition of the protein synthesis intensity, while serotonin has a contrary action, that under conditions of subsequent irradiation provides an increase in the synthesis level of histones and nonhistone proteins. Possible mechanisms of the irradiation and serotonin effect on the synthesis processes of chromatin proteins in the organism are discussed.

[Enzyme activity in rat intestines after exposure to x-irradiation]. / Aktyvnist' travnykh fermentiv kyshky shchuriv pislia diï renthenivs'koho vyprominiuvannia.

It is established that 24 hours after total X-ray irradiation by doses of 0.5, 1 and 2 Gy activity of intestine enzymes (saccharose and alpha-amylase) increases. A dose of 3 and above induces an increase of saccharose activity and inhibition of alpha-amylase. The functional state of basic phosphatase under action of the doses investigated remains practically unchanged.

[Synthesis and phosphorylation of histones and nonhistone proteins as affected by irradiation and serotonin in cycloheximide-synchronized hepatocytes]. / Sintez i fosforilirovanie gisotonov i negistonovykh belkov pod vliianiem oblucheniia i serotonina v sinkhronizirovannykh tsiklogeksimidom gepatotsitakh.

Phosphorylation and synthesis of histones and nonhistone proteins were studied after the inhibition of translation by sublethal cycloheximide doses. Activation of the chromatin protein phosphorylation was noted: (1) at the stage of recovery and stimulation of the protein synthesis (18-24 h), and (2) at the stage of activation of the replicative DNA synthesis (30-60 h). Phosphorylation and synthesis of the chromatin proteins depended upon the individual or combined effect of X-radiation and serotonin. The authors discuss the possible role of the chromatin protein phosphorylation in the response of the nuclear apparatus to the effect of radiation and serotonin the latter being used as a radioprotective agent.

[Cyclic nucleotide levels in the regenerating liver of rats following irradiation and protection by serotonin]. / Urovni tsiklicheskikh nukleotidov v proliferiruiushchei pecheni krys posle oblucheniia i v usloviiakh zashchity serotoninom.

Changes in cAMP and cGMP levels after X-irradiation and radioprotective treatment with serotonin were studied using a model of impulse inhibition and repair of transcription, translation and replication by cycloheximide in rat hepatocytes in vivo. Irradiation was shown to inhibit the cyclic nucleotide synthesis. Serotonin increased the contents of cAMP and cGMP maintaining their elevated level after X-irradiation.

[DNA synthesis in the liver of irradiated and serotonin-protected rats after removal of the cycloheximide block]. / Izuchenie sinteza DNK pri obluchenii i zashchite serotoninom v pecheni krys posle sniatiia tsiklogeksimidnogo bloka.

The cycloheximide block model was proposed to study the mechanism of action of both radiation and radioprotectors. It was shown that irradiation of proliferating hepatocytes in vivo, at early stages of the prereplicative phase, markedly inhibited DNA synthesis. Serotonin, in its turn, considerably increased DNA synthesis maintaining this increase after subsequent exposure to X-radiation.