[Regulating activity of plasma membranous Ca2+ channels in PC-12 pheochromocytoma cells with chemicals and pharmaceutic agents].

The activity of the voltage-operated Ca2+ channels (VOC channels) and store-operated Ca(2+)-channels (SOC channels) was studied on rat pheochromatocytomic cells PC-12 by using the fluorescence calcium dye Fura-2. The VOC channels were transferred in their open state by depolarizing the plasma membranes of the cells through addition of high KCl concentrations (50 mM). The SOC channels were activated by treating the cells with tapsigargine, a special inhibitor of Ca2+ ATPase in the intracellular Ca2+ stores.

[The effect of sodium nitroprusside and nitro-containing vasodilators on rat liver microsomal mono-oxygenases].

It has been shown in vitro that sodium nitroprusside (SN) causes a concentration-dependent suppression of the enzymatic activity of aminopyridine demethylase-APDM(IC50 = 1.86 x 10(-4) M) and ethoxycoumarin O-deethylase-ECOD(IC50 = 1.46 x 10(-4) M) in hepatic microsomes of Wistar rats, which is related to different isoforms of cytochrome P-450.

[A preclinical evaluation of the pharmacological activity of a mixed potassium and magnesium glutamate].

Mixed magnesium and potassium glutamates with different ion ratio are synthesized. The antiarrhythmic activity of the compounds obtained is studied on the models of strophantin, calcium chloride, aconitine arrhythmia, and arrhythmia after Harriss. It is found that magnesium and potassium glutamate of the composition KMg(HGlu)4.

[The pharmacological properties of coenzyme A disulfide].

Coenzyme A disulfide (CoA disulfide) was pharmacologically studied. It has been found to normalize lipid and carbohydrate metabolism when given in a dose of 2 mg/kg, i.m.

[The metabolism and biological activity of glucuronidation substrates in experimental diabetes mellitus].

The study was undertaken to examine the impact of experimental diabetes mellitus on the biotransformation of some drugs, their toxicity and hypoglycemic action, as well as on the biotransformation of endogenous testosterone and the androgenic status. The accelerated metabolism of both exogenous and endogenous substrates which occurred in diabetes mellitus caused a decrease in their biological activity.

[A metabolic study of the synthetic glucocorticosteroids prednisolone and dexamethasone in the body of white rats and in in-vitro reactions].

The metabolism of the synthetic steroidal hormones prednisolone and dexamethasone was studied in albino rats and in in vitro microsomal oxidation system by using high performance chromatography and radioactive tracers. Dexamethasone was found to be metabolically stable. The first step of prednisolone biotransformation is formation of prednisone during the NADPH-dependent reaction catalyzed by microsomal enzymes.

[Drug derivatives of xanthine].

The data on the pharmacological effects of xanthines and their use in pharmacotherapy, particularly, in regulation of cellular hemostasis to correct disorders of microcirculation are summarized. The possible mechanisms of hemostasis regulation by xanthines and the most promising ways of search for new antiaggregation drugs in this series are considered.

[The dynamics of prednisolone and dexamethasone distribution and metabolism in the body of white rats].

The processes of elimination and distribution of the synthetic steroidal drugs prednisolone and dexamethasone in the internal organs of Wistar rats were studied by the method of radioisotopes and high performance liquid chromatography. It was shown that the main route of excretion is the elimination with the urine. Prednisolone does not undergo conjugation and dexamethasone is glucuronidated by approximately 20%.

[Methodologic problems of pharmacokinetics].

The subject of pharmacokinetics, method of research, aims and tasks of fundamental and applied aspects, place and importance for pharmacology are discussed. Discrepancy between a high scientific potential of pharmacokinetics and a low practical realization are analyzed, priority trends of future research are formulated.

[Change in carbohydrate metabolism, secretion of insulin and glucagon in normoglycemic rats during administration of various doses of nicotinamide].

Development of hypoglycemia, a slight decrease in concentration of glucagon in blood as well as increase in activity of malate-and glucose-6-phosphate dehydrogenases in liver cytosol were detected in rats injected subcutaneously with nicotinamide at a dose of 31.25 mg/kg 6 hrs before decapitation. Increase of the single dose up to 125 mg/kg caused hypoglycemia, distinct increase in concentration of insulin and glucagon in blood plasma simultaneously with a pronounced inhibition of the enzymatic activity in liver tissue.

[Effect of nicotinamide on body glucose utilization in animals].

A single administration of nicotinamide (62.5 mg/kg) was found to enhance the relative activity of exogenous insulin, to decrease glucose level in the peripheral blood, to increase the activity of malate dehydrogenase and glucose-6-phosphate dehydrogenase in the liver cytosol in intact mice and to increase the rate of exogenous glucose utilization in rabbits. The character of nicotinamide effect on carbohydrate metabolism in intact animals is suggested to be dose-dependent.

[Metabolic products of methandrostenolone in the body of white rats studied by high-performance liquid chromatography].

Metabolism of the anabolic steroidal hormone methandrostenolone in Wistar rats was studied by high performance liquid chromatography (HPLC) and redioisotope techniques. The conditions for isolation of methandrostenolone metabolites by HPLC were developed. Reduction of the double bonds was shown to be an early stage in methandrostenolone biotransformation.

[Dynamic distribution of methandrostenolone in the body of white rats].

Dynamics of distribution of anabolic steroidal hormone methandrostenolone and routes of its elimination from the organism of Wistar rats were studied by using methods of radioisotopes and high-performance liquid chromatography. Methandrostenolone metabolites were shown to be excreted mainly in the urine. Methandrostenolone metabolism is a complicated process in the course of which redistribution of metabolites among various organs occurs.

[Hormonal metabolic status of the human body under the conditions of the Far North].

The concentrations of hormones (ACTH, cortisol, aldosterone, thyrotrophin, thyroxine, triiodothyronine, growth hormone, insulin, prolactin and testosterone), electrolytes (Na and K) as well as glucose and triglycerides were measured in 10 athletes who made a 380 km ski expedition in the Far North at ambient temperatures of -32 to -34 degrees C. Human adaptation to the geographic and climatic conditions of high latitudes was accompanied by noticeable changes in the incretory function of the adenopituitary, thyroid gland, adrenals and gonads. The data obtained indicate that a ski trip in the Far North produces a distinct stress with physical and cold components being predominant.

[Microbiological method of determining cyanocobalamin in tissues and finished drugs made from animal raw materials].

An assay for cyanocobalamin with the use of the test microorganism E. coli, mutant ATCC 9637, is offered. The measurement of the content of cyanocobalamin in the blood serum and liver of intact rats after intraperitoneal drug injection demonstrated its content to reach a maximum 30 minutes after injection and to depend on the dose.

[Acetylation of sulfadimezine and ethazole in rats].

The paper is concerned with studies into acetylation of sulfadimezine (S) in Wistar, August and random-bred rats and into that of ethazole in Wistar rats. Age-associated differences in S acetylation were examined in random-bred animals and the effect of phenobarbital on S acetylation was investigated in Wistar and August rats. Interlinear differences as regards S acetylation were found to be absent in the presence of sexual dimorphism as to the sign under study: the females were disclosed to be rapid while males to be slow S acetylators.

[Kinetic analysis of induced platelet aggregation].

Two mathematic models depicting the kinetics of induced platelet aggregation are suggested. The mechanisms of platelet aggregation involving the reactions of the inductor molecules with membrane receptors and intercellular interactions of platelets are discussed. Analytical expressions depicting the changes in the amount of platelets in the aggregation population and in the course of aggregation are offered.

[Participation of cyclic nucleotides in the mechanism of regulation of the tissue pool of coenzyme A and the acetylizing capacity of rats].

cAMP and dibutyryl-cAMP were shown to increase the pool of CoA (or all the pantothenic coenzymes) in rat liver tissue, especially after treatment of the animals with 4-phosphopantothenate but not with pantethine. As shown by experiment with inhibitors of protein synthesis (actinomycin D, actidion, chloramphenicol) immediate c-AMP-dependent stimulation of the biogenesis of pantothenic coenzymes occurred rather from their precursors than due to induction of enzymes, participating in the biogenesis, or to destruction of the pantothenic coenzymes. Experiments with chloramphenicol exhibited that cAMP regulation of the biogenesis of pantothenic coenzymes in mitochondria was responsible mainly for the cellular pool of CoA and, partly, for the acetylation of para-aminobenzoic acid in tissues.