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Biomedical subjects

O P Cherkasova

Publications and source records attributed to O P Cherkasova.

15 recordsLinked to original sources
PubMed2006

Activity of 11beta-hydroxysteroid dehydrogenase in tissues of hypertensive NISAG rats.

11beta-Hydroxysteroid dehydrogenase activity in the kidneys of NISAG rats (rat strain with hereditary stress-induced arterial hypertension) was 1.5-fold higher than in WAG rats. An inverse relationship was observed in the liver of these animals. After stress exposure 11beta-hydroxysteroid dehydrogenase activity remained unchanged in the kidneys of NISAG and WAG rats, but significantly increased in the liver of NISAG rats. Functional activity of 11beta-hydroxysteroid dehydrogenase probably reflects the hypertensive state of NISAG rats.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2006

Prolonged decrease in stress reactivity caused by dehydroepiandrosterone sulfate.

In male rats exposed to repeated stress, the decrease in stress reactivity produced by subcutaneous injection of dehydroepiandrosterone sulfate (recorded by the decrease in stress-induced concentrations of corticosterone and adrenocorticotropic hormone in blood plasma) was observed 1-6 days postinjection and involved central regulatory mechanisms.

Adrenocorticotropic Hormone↗
PubMed2005

Activity of angiotensin-converting enzyme in hereditary stress-induced arterial hypertension.

We measured activity of angiotensin-converting enzyme in plasma and tissue of NISAG and normotensive WAG rats. In different organs of NISAG rats, activity of this enzyme did not differ from the corresponding values of WAG rats, although enzyme activity in the plasma of NISAG rats was significantly lower than that of WAG rats. Since NISAG rats are characterized by low activity of renin in the renal cortex, it is hypothesized that NISAG rats simulate the low-renin hypertension, in which inhibition of activity of the angiotensin-production system results from elevation of arterial pressure of central origin.

Animals↗
PubMed2004

Ratio between the contents of 11-dehydrocorticosterone and corticosterone after acute and repeated stress: effect of dehydroepiandrosterone sulfate.

Acute stress was accompanied by reduction of 11-dehydrocorticosterone to corticosterone in male rats. The reverse reaction predominated during repeated stress and increased after administration of dehydroepiandrosterone sulfate. Treatment with mu-opioid receptor antagonist naltrexone in a dose of 0.1 mg/kg 20 min before administration of dehydroepiandrosterone sulfate abolished this effect.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗
PubMed2003

Stress-limiting effect of dehydroepiandrosterone sulfate and its mechanism.

Dehydroepiandrosterone sulfate prevented the increase in corticosterone level in rats induced by repeated exposure to stress. The mu-opioid receptor blocker naltrexone administered in a dose of 0.1 mg/kg 20 min before treatment with dehydroepiandrosterone sulfate abolished the effect of this agent. Dehydroepiandrosterone sulfate and naltrexone had no effect on rats after acute stress.

Animals↗
PubMed2003

[Characteristics of glucocorticoid receptor gene expression in spontaneously hypertensive rat strain].

In ISIAH rat strain with stress-sensitive form of hypertension, the expression level of glucocorticoid receptor (GR) gene has been evaluated in hippocampus, hypothalamus and pituitary under basal and 2-hr restraint stress conditions. Corticosterone (CS) level in peripheral blood was also evaluated. Normotensive WAG strain was used as a control. Under basal condition, there were no interstrain differences in GR-mRNA level in any brain region under study. However, under stress condition, ISIAH rats demonstrated a significant fall of GR-mRNA in hippocampus and increase the pituitary gland as compared to basal level. On the contrary, no differences with basal level were found in stressed WAG rats. CS concentration in blood was nearly the same in nonstressed WAG and ISIAH rats. Stress influence led to a marked increase of CS in both strains. However CS level was significantly higher in stressed ISIAH rats than in stressed WAG group.

Animals↗
PubMed2002

[Influence of diet without added bran on the contents of corticosteroid hormones in adrenal gland and blood plasma of rats].

The article is devoted to the influence of one-bran diet on functioning adrenal gland. There was investigated a level of corticosteroid and 11-dehydrocorticosterone in blood and adrenal gland rats and also aldosterone and desoxycorticosterone in adrenal gland. The consumption of one-bran diet results in increase of a corticosterone level in blood and contents of 11-dehydrocorticosterone in adrenal gland and thus is a stressful factor. The transition of animals on to a vivarium standard diet does not remove this condition completely.

Adrenal Glands↗
PubMed2002

[Effect of dehydroepiandrosterone sulfate on stress reactivity: mu-opioid mechanism].

The dehydroepiandrosterone sulfate (DHEAS) effect on stress-reactivity and the role of mu-opioid receptors in it, were studied. The experiments were carried out in male rats. The shuttling in single or in multiple (19 days, for 1 hour a day) regimes served as the experimental stress influences. The estimation of stress-reactivity was carried out by the plasma corticosterone level. It had been shown that the subcutaneous injection of dehydroepiandrosterone sulfate in rats reduced the stress-induced increase in corticosterone levels under the multiple influences, whereas naltrexone (0.1 mg/kg, for 20 min before DHEAS injection) blocked this effect. There were no effects of DHEAS or naltrexone on corticosterone levels under the single stress influences.

Animals↗
PubMed2001

[Measurement of plasma renin activity using fluorescent substrate renin].

Direct chromatographic method for measuring renin activity by high-performance liquid chromatography has been developed. The method is based on enzymatic hydrolysis of a new fluorescent substrate renin with formation of fluorescent angiotensin I (fAI). The content of fAI is evaluated by a calibration curve reflecting a linear relationship between the ratio of fAI and internal standard areas and the amount of resultant fA1 in reaction mixture. 100 microliters plasma is needed for analysis. After 1-h incubation at 37 degrees C the reaction mixture is introduced directly into chromatographic system with a precolumn. Acetonitrile gradient in 0.05 M Tris-TPU buffer (pH 8.0) allows a satisfactory separation of hydrolysis products. The sensitivity of the method is 100 pg fAI/ml. The method adequately reflects species characteristics of plasma renin activity and its changes caused by stimulation of renin secretion, is characterized by higher selective activity than radioimmunoassay, and is more rapid.

Angiotensin I↗
PubMed1997

[The effect of a stable acetylcholine analog on angiotensin-converting enzyme activity in the lung, kidney and arterial blood plasma of rats with increased sympathetic activity].

Anesthetised rats with sympathetic overactivity were selected by previous testing on the base of the plasma level of corticosterone, norepinephrine and epinephrine, arterial pressure reactivity on epinephrine and acetylcholine injections, and difference between carotid and tail arterial pressure. Basal ACE activity in kidney, lung, and arterial plasma of such rats was in 5, 3 and 1.7-fold more than in mesotonic rats, respectively. I.v. administration of carbachol (10(-9) and 10(-8) mol/kg) produced decrease in arterial plasma ACE activity in dose-dependent manner (from 40 to 20 nmol/ml.min) and diminution of lung ACE activity (on 18%). It is suggested that carbachol produces an inactivation and inhibition of ACE secretion by lung and lung ACE biosynthesis in sympathetic overactivity rats. A pattern of ACE activity in plasma, kidney and lung is determined by the sympathetic-parasympathetic balance.

Acetylcholine↗
PubMed1989

[Analysis of corticosteroids in blood plasma using a microcolumn liquid chromatography method].

A microcolumn variant of high-pressure liquid chromatography of human blood plasma corticosteroids using Milikhrom, a Soviet chromatograph, is suggested. The analysis involves hexane treatment of the plasma, chloroform extraction of corticosteroids, concentration of the extract, and chromatography in a 60 X 2 mm column packed with Silasorb sorbent, sph C18 (7.5 micros), methyl alcohol/water mixture (52:48) at a rate of 100 microliter/min and a detection wavelength 240 nm. The method permits an analysis of cortisone, hydrocortisone, corticosterone, and other corticosteroids with concentrations higher than 4 ng/ml.

Adrenal Cortex Hormones↗
PubMedDate not supplied

[The peculiarities of fluorescence of natural steroid hormones, excited by a laser source of the UV range].

The data of studies were summarized that demonstrated for the first time the fluorescence of the members of all classes of steroid hormones. The fluorescence spectra were characterized, the relative fluorescence quantum yields were estimated, and the dependence of the intensity and spectrum of fluorescence on the presence and position of side groups and double bonds in the molecule of the hormone was established.

Fluorescence↗