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P A Kaliman

Publications and source records attributed to P A Kaliman.

5 recordsLinked to original sources
PubMed1991

The effect of tryptophan on the phenobarbital-mediated induction of cytochrome P-450 in rat liver. The role of tryptophan 2,3-dioxygenase.

The effect of intraperitoneal administration of phenobarbital (80 mg kg-1 body weight) and tryptophan (200 mg kg-1 body weight), separately or in combination, on the microsomal content of cytochrome P-450 and the activity of tryptophan 2,3-dioxygenase (EC 1.13.11.11) in Wistar rat liver was determined at different time intervals after injection. There was an increase in the amount of cytochrome P-450 within 12 h of administration of a single dose of phenobarbital which was maintained over the next 12 h. Tryptophan had no effect on the amount of cytochrome P-450, but administration of tryptophan in combination with phenobarbital blocked the increase that was found after administration of phenobarbital alone. Both phenobarbital and tryptophan increased tryptophan 2,3-dioxygenase activity (total enzyme and holoenzyme) but had different effects on the rate of activation and the degree of saturation of the enzyme with haem. Administration of tryptophan and phenobarbital in combination invoked the same effect as tryptophan alone. Significant activation of the holoenzyme was found, when tryptophan was administered 2 h after phenobarbital administration. It is proposed that combined administration of phenobarbital and tryptophan leads to substrate stabilisation of tryptophan 2,3-dioxygenase, and that this is accompanied by the binding of the newly synthesised haem, thus making haem unavailable for formation of cytochrome P-450.

Animals↗
PubMed1991

[The effect of copper and insulin on nucleic acid and protein synthesis in Tetrahymena pyriformis cells under different functional conditions].

The effect of copper ions and insulin on the rate of DNA, RNA and protein synthesis, and on the growth dynamics of Tetrahymena pyriformis cells, and also joint action of Cu2+ and insulin on these processes has been investigated. The effect of Cu2+ after 6-fold action of heat shock (34 degrees C) on the cell culture has been studied. The results obtained indicate that significant reconstructions of the infusoria cell functioning conditions caused by various reasons re of great importance in the adaptation mechanisms to such stress factors as heavy metals.

Animals↗
PubMedDate not supplied

[Dynamics of RNA synthesis and transport into the intact and regenerating rat liver in the presence of sublethal doses of actinomycin D].

The time-dependent characteristic of RNA synthesis has been studied against the effect of sublethal doses of actinomycine D in cells with different proliferative activity, connection of synthesized RNA with RNP-particles of nuclei and its transport into the ribosomes and cytoplasmic postribosomal fraction. Against a background of actinomycine D sublethal doses (150 and 300 micrograms per 100 g body weight) from 0.5 to 4% of RNA is synthesized in comparison with the original level. The level of specific radioactivity of RNA depends on the original functional state of the liver. The newly synthesized RNA is found in the nuclei RNP-particles and transported into the cytoplasm. It is localized in ribosomes (2-3% in intact and about 6% in regenerating liver from the original level) and in the postribosomal fraction (8-10% and 16-18% in intact and regenerating liver, respectively. It is supposed that RNA synthesized against the effect of sublethal doses of actinomycine D takes part in conservation and restoration of realization of genetic information system activity, that is observed 12 hours after the antibiotic injection.

Animals↗
PubMedDate not supplied

[Activity of cytoplasmic NADP-dependent dehydrogenase in rat liver during induction of cytochrome P-450 by phenobarbital].

Activity of oxidation enzymes of the pentosephosphate way (glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44), cytoplasmic malate dehydrogenase (decarboxylating oxaloacetate) (NADP+) (EC 1.1.1.40) and isocitrate dehydrogenase (NADP+) (EC 1.1.1.42) as well as the content of microsomal cytochromes b5 and P-450 in the rat liver have been studied 24 hours after 1, 2, 3, 4 and 5 intraperitoneal administrations of phenobarbital (4 mg per 100 g of the body weight). It is shown that the cytochrome P-450 content increases after a single administration of phenobarbital and then it gradually grows reaching its maximum after 4 administrations and falls after 5 administrations (though it remains high as compared to the control animals). The content of cytochrome b5 increases only after 4 administrations of phenobarbital and after 5th one it returns to the initial level. The content of microsomal gangliosides calculated per 1 mg of microsomal protein decreases after a single administration of phenobarbital and 5 days later it returns to the initial level. Activity of glucose-6-phosphate dehydrogenase increases after a single administration of phenobarbital, that of malate dehydrogenase--after 3 administrations, 6--phosphogluconate-dehydrogenase--after 4 administrations of the preparation. The 5 administrations of phenobarbital makes activity of all the mentioned dehydrogenases return to the initial level. Activity of isocitrate dehydrogenase under given conditions of the experiment does not change.

Animals↗