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Biomedical subjects

T Smirnova

Publications and source records attributed to T Smirnova.

26 records · Page 2Linked to original sources
PubMed1990

Changes of beta-endorphin level in blood during prolonged exercise.

In 49 healthy subjects during 2 h exercise on bicycle ergometer four variants of changes of beta-endorphin level were observed: 1. an increase during first 30 min followed by a decreased below initial values; 2. biphasic increase (peak values at the 30th and 120th min); 3. increase only during the 2nd h of exercise; 4. decrease during the whole period of exercise. For trained subjects the most common was the biphasic increase, for untrained ones--the overall decrease.

Adrenocorticotropic Hormone↗
PubMed1989

Renal urea clearance in normal and adrenalectomized rats after exercise.

In groups of male Wistar rats, blood level, urinary excretion of urea, and renal urea clearance were determined in resting conditions or during 48-60 h after swimming for 30 min with an additional load of 10% of body weight as well as after swimming for 3 or 10 h without additional load. Both types of swimming exercise caused a significant increase in the blood level, urinary excretion, and renal clearance of urea. After 10-h swimming, the increase of renal urea clearance was observed only from the second period (0-12 h) of urine collection. In this type of exercise, an elevation of blood level of corticosterone was obtained after 6-h restitution. The increased urinary excretion and renal urea clearance persisted for a longer time than was necessary for the normalization of the blood level. A significant rise in blood urea level and a drop in renal urea clearance occurred after adrenalectomy. In adrenalectomized rats, increased urea excretion and renal clearance were observed 12-24 h after 3-h swimming, but the level of renal clearance obtained in sedentary normal rats was not achieved. The blood level of urea did not increase. This suggested that the glucocorticoids play a role both in urea formation during exercise and in its elevated renal clearance after exercise.

Adrenalectomy↗
PubMed1989

Biochemical changes in blood during the long and short triathlon competition.

The purpose of the study was to compare the effects of long (3.8 km swimming, 180 km biking, 42.2 km running, n = 7) and short (1.5 km swimming, 42 km biking, 14 km running, n = 14) triathlons on blood hormones, metabolites and substrates. Both variants of triathlon caused a significant rise in cortisol, somatotropin and aldosterone levels, the insulin and C-peptide levels decreased. The progesterone level increased considerably only after long triathlon. The testosterone level did not change essentially. The level of plasma glucose, total cholesterol, HDL, LDL did not change substantially during the both competitions. FFA concentration increased significantly and triglycerides concentration decreased only during the prolonged variant.

Adult↗
PubMed1987

Crystal protein formed by Bacillus subtilis cells.

Electron microscopic investigation of ultrathin sections of Bacillus subtilis Cgr4 cells revealed the presence of crystal-like inclusions which were formed of spheric homogeneous subunits. The frequency of cells with a crystal-like inclusion in the culture approached 1%. The appearance of the crystal protein in cells coincided in time with spore morphogenesis. However, the process of crystal protein formation and sporulation are two alternatives: the cells either form the crystal protein or continue spore morphogenesis. Fractionation of cells in the stationary growth phase on a Percoll density gradient showed that the cells containing the crystal protein accumulated in the fraction corresponding to a 1.14-g/ml Percoll density. The cells were disintegrated by sonication, and alkaline-extracted proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After sodium dodecyl sulfate-gel electrophoresis, the fraction enriched with crystal-containing cells showed practically a single band with a molecular weight of 47,000 that corresponded to the crystal-forming protein. The antigenic features and amino acid composition indicated certain similarities between the crystal-forming protein in B. subtilis Cgr4 cells and the spore coat protein.

Amino Acids↗
PubMed1985

Involvement of protein synthesis in the action of glucocorticoids on the working capacity of adrenalectomized rats.

The administration of cortisol for 3 or 5 days increased the maximal duration of swimming under additional load, equal to 3% of body weight, in adrenalectomized but not in intact Wistar rats. The liver tryptophan oxygenase activity also increased. The blockade of RNA synthesis by actinomycin D excluded both results of cortisol administration. High doses of progesterone (25 or 75 mg/day) decreased the working capacity, rendering the action of cortisol on the working capacity of adrenalectomized rats insignificant. However, the antagonism between two hormones was not striking at the level of liver tryptophan oxygenase induction. The results suggest that the action of glucocorticoids on the working capacity is mediated by RNA and, further, by protein synthesis. The competition for glucocorticoid cytoplasmic receptors, to be found between glucocorticoids and a high level of progesterone, can disturb this mechanism. The synthesis of hepatic enzyme proteins is not responsible for the action of glucocorticoids on the working capacity.

Adrenal Glands↗
PubMed1982

Independence of physical working capacity from increased glucocorticoid level during short-term exercises.

To investigate the influence of glucocorticoid levels on the physical working capacity, 18 trained and 18 untrained male subjects were examined before and after a short-term graded exercise test. By administration of dexamethasone during 3 days prior to the test or by injecting 25 U of corticotropin 30 min pre-exercise, the blood cortisol response to exercise was altered. It was found that the physical working capacity, as evaluated by PWC170, maximal oxygen deficit, and maximal pedaling rate were not influenced by the glucocorticoid response to the test. It is suggested that the effects of metabolic processes induced by adrenocortical response to exercise are seen only after a lag period.

Adrenocorticotropic Hormone↗