Biomedical subjects

V A Kokunin

Publications and source records attributed to V A Kokunin.

23 records · Page 2Linked to original sources

PubMedDate not supplied

[Dependence between the rate of RNA synthesis and the CTP-synthetase activity of different rat and chicken tissue].

The rate of total RNA synthesis determined by the method of Bukher and Sheffield in different tissues of rats and chickens decreases as follows: kidneys greater than liver greater than duodenum mucosa. The activity of CTP-synthetase (EC 6, 3, 4, 2) determined in vitro and in vivo by the method suggested correlates with the rate of total RNA synthesis in the kidneys and liver tissues of rats and chickens. It is shown that 34-35% of CTP synthetized de novo in the chicken tissues and 31-34% in the rat tissues are used for RNA synthesis. At the same time 75-90% of CTP incorporating into RNA is formed by salvage pathway.

Animals↗

PubMedDate not supplied

[Dependence of calcium absorption in the chicken small intestine on its Ca2+-binding protein content and the effect of exogenous nucleotide precursors on this process].

A dependence was studied between the level of calcium absorption and the content of calcium-binding protein in the small intestine of D-hypovitaminous chickens to whom different exogenic precursors of nucleotides (potassium orotate or guanine) were administered at different stages of the response (0-72 h) to a single administration of vitamin D3 in a dose of 500 MU. It is established that under the effect of potassium orotate or guanine the degree of discrepancy between calcium adsorption and the content of Ca2+-binding protein increases at all stages under investigation. The results of the mathematical analysis of the experimental data which is based on the supposition of the linear dependence between the level of absorbed calcium and Ca2+-binding protein evidence for a considerable rise in the excess amount of the latter, which possibly does not take part in cation absorption, in the chickens who were administered nucleotide exogenic precursors. The data obtained show that the amount of calcium-binding protein is not a limiting factor in the mechanism of vitamin D3 stimulation of calcium absorption in the chicken small intestine.

Animals↗

PubMedDate not supplied

[Hypolipidemic action of liposome-incorporated beta-sitosterol on rats].

Daily administration to rats with experimental hypercholesterolemia of beta-sitosterol (5 mg/kg) contained by lecithin liposomes provoked a 25% reduction in blood plasma cholesterol in 3 weeks, whereas crystalline beta-sitosterol (50 mg/kg) produced an analogous effect in 6 weeks. The drug under study decreased the level of atherogenic beta-lipoproteins in blood plasma and intestinal mucosa, raised the content of phospholipids in blood plasma and normalized the cholesterol/phospholipid ratio. The drug high hypolipidemic activity was supported in experiments in vitro with inverted sacs of the small intestine. The drug was found to be long-acting.

Animals↗

PubMedDate not supplied

[Concentration of free nucleotides and turnover of adenine nucleotides in the liver of birds of different ages].

The content of free nucleotides and exchangeability of adenine nucleotides were studied in the liver of 1- and 18-month cocks. It is established that adenine nucleotides in the young cocks liver account for 40%, uridine nucleotides for 29%, cytidine nucleotides for 13% of the total amount of nucleotides. These ratios are maintained with age but the amount of adenine nucleotides decreases by 35% and that of uridine nucleotides by 22%. Against a background of a relatively constant level of adenine and uridine nucleotides the content of cytidine and guanine nucleotides varies synchronously within wide ranges, which can evidence for the presence of a common mechanism of regulating synthesis of these metabolites. A direct correlation is detected between the amount of adenine nucleotides and their specific radioactivity. This is due to a higher intensity of synthetic processes in young cocks. The inverse correlation is observed in adult cocks, that results from the effect of "label dilution".

Adenine Nucleotides↗

PubMedDate not supplied

[Carboxylation intensity in the liver of birds of different ages].

Carboxylation intensity was studied in the liver of young and adult cocks, 14C-bi-carbonate was used as an indicator of the amino acids, proteins and lipids turnover. It is established that the amount of dry residue in the liver tissue of the adult cocks is 22% higher and that of pyruvate and dicarboxylic amino acids is twice as low. The relative weight of the liver changes with age: in the 18-month-old cocks it is 1.5%, in the one-month-old cocks, 2.75%. The maximum of 14C incorporation into the tissue, dicarboxylic compounds, proteins and lipids of young cocks in the in vivo experiments is at a shorter exposure of the isotope. 14C removal from these compounds in the young cocks occurs more quickly as well. A higher radioactivity of the compounds under study in the adult cocks liver with prolongation of the isotope exposure is due to the effect of factors which are not related to the synthesis. The experiments established that radioactivity of proteins and lipids in the young cock liver slices is 6 times as high at 60-minute exposure. The mentioned above evidences for a higher rate of carboxylation in young cocks as compared to adult ones. When interpreting the data of metabolism study by means of isotopes in animals of different age a corrections should be made for a change in the liver relative weight during the growth process.

Age Factors↗