[Effect of natural zeolites on renal functions and water-salt metabolism in rats]. / Vliianie prirodnykh tseolitov na funktsii pochek i vodno-solevoi obmen u krys.

In vivo experiments on adult Wistar rats, it has been found that intake of natural zeolites resulted in temporary decrease of renal water, sodium and potassium excretion. At the same time, reabsorption of water and electrolytes increased. This effect was due to the stimulation of Na+, K(+)-ATPase activity in thick ascending limb of Henle loop and hormonal changes: increase of insulin, thyroxin and aldosterone concentration in plasma. The water and ion content in most of the tissues under study was higher in the experimental group than in control. It has been suggested that renal response in rats with zeolites intake was compensatory lower as a result of gastrointestinal losses of ions and ion accumulation in tissues.

[Hormonal regulation disorders in vibration disease pathogenesis]. / Narushenie gormonal'noi reguliatsii v patogeneze vibratsionnoi bolezni.

The authors studied humoral regulation state in vibration disease patients. Correlation analysis proved role of hormonal disturbances in pathogenesis of angiopathies and visceropathies characteristic for vibration disease.

Development of hypertensive status in NISAG rats reared by normotensive Wistar rats.

Parameters of the cardiovascular system and the content of corticosterone, thyrotrophin, thyroxin, and triiodothyronine in the plasma, and norepinephrine in the myocardium were determined in male NISAG rats (hereditary stress-induced arterial hypertension) reared by normotensive Wistar rats. Cross-rearing of hypertensive rat pups by normotensive females attenuated arterial hypertension with a tendency to normalization of the examined parameters. This confirms the possibility of modifying hypertensive phenotype by changing the conditions of the early postnatal development.

Functions of the hypothalamo-hypophyseal-adrenal system in aging in female monkeys.

Comparative studies on the functioning of the adrenal cortex in female rhesus macaques (Macaca mulatta) of different ages are reported - animals were aged 6-9 years (young adults; n = 5) and 20-26 years (old adults; n = 5). Corticosteroid concentrations (cortisol (F) and dehydroepiandrosterone sulfate (DHEAS)) were determined by specific radioimmunological and immunoenzyme methods in basal conditions, after acute stress (insulin-induced hypoglycemia, 2-h movement restriction), and after administration of dexamethasone. Basal F levels showed no marked age differences, while DHEAS concentrations in older animals decreased sharply. These animals also demonstrated weakened adrenal cortex responses to movement restriction, giving rise to delays in reaching peak F and DHEAS levels and decreases in the areas under their response curves (AUC) during the 4-h study period. In the dexamethasone test, the hypothalamo-hypophyseal-adrenal system of monkeys aged 20-26 years was relatively resistant to the suppressing effect of glucocorticoids via the negative feedback mechanism. It is suggested that disruption of feedback in the system controlling adrenal cortex function may be at least partially due to the development of peripheral blood steroid dysbalance with aging, this consisting particularly of a decrease in the DHEA (DHEAS) level; this steroid is known for its neurological activity.

[Sensitivity of the pituitary-ovarian system of animals to the nonhormonal preparation RL-S]. / Chuvstvitel'nost' gipofizarno-ovarial'noi sistemy zhivotnykh k negormonal'nomu preparatu RL-S.

A hypophysis-ovarian system of barren cows was shown to be highly sensitive to the effect of the preparation RL-S. The preparation possessing a simple chemical structure, proved to regulate the functional activity of endocrine glands. After treatment with the preparation RL-S concentration of estradiol was increased 1.81-fold in blood plasma of cows studied as compared with controls, while content of luteinizing hormone was elevated by 12.3%. In the groups of experimental animals the sexual cycle was normalized as content of progesterone was increased in blood with simultaneous decrease in estradiol concentration.

[Hormonal activity of the hypophysis-gonadal system in male hamadryas baboons in relationship to their hierarchical position]. / Gormonal'naia aktivnost' sistemy gipofiz-gonady u samtsov pavianov gamadrilov v zavisimosti ot ikh ierarkhicheskogo polozheniia.

Hierarchic status-dependent hormonal activity of pituitary-gonadal system was studied in an isolated group of hamadryas baboons. Testosterone level was higher in dominating males. The level of sex hormone was higher in aged animals with great muscle mass. No correlation was observed between hierarchic status of hamadryas baboon males and the blood level of luteinizing hormone.

[Androgen content of the blood of male hamadryas baboons over the course of a year]. / Soderzhanie androgenov v krovi samtsov pavianov gamadrilov na protiazhenii goda.

Annual blood plasma levels of testosterone, 5 alpha-dehydrotestosterone and dehydroepiandrosterone were measured in hamadryas baboon males using radioimmunoassay. Fluctuations characterized by a decrease in testosterone and 5 alpha-dehydrotestosterone concentrations in spring and an increase in their levels in autumn have been established. Dehydroepiandrosterone level was characterized by two minimal points--at the beginning of the year and in August. The following average annual levels of androgens have been determined: 22.5 nmol/l for testosterone; 4.7 nmol/l for 5 alpha-dehydrotestosterone; 19.0 nmol/l for hydroepiandrosterone.

[Effect of RL-175 on testosterone and corticosterone levels in the plasma of male albino rats]. / Vliianie RL-175 na soderzhanie testosterona i kortikosterona v plazme krovi belykh krys-samtsov.

After feeding of male rats with the chemical preparation RL-175 a 1.5-fold increase in the testosterone content and more than 2-fold increase of corticosterone were found in blood as compared with control values. Considering that hypothalamus less than the front zone of hypophysis greater than and the endocrinal glands are the most important tissues in sexual and adaptational regulation, the drug RL-175 can be used for treatment of the diseases developing with age, i.e. caused by the inner factors.

[Functional activity of the adrenal system in relation to the hierarchical status of male hamadryas baboons in an isolated group]. / Funktsional'naia aktivnost' nadpochechnikovoi sistemy v sviazi s ierarkhicheskim polozheniem samtsov pavianov gamadrilov v izolirovannoi gruppe.

The correlation between hormonal activity of hypophysis-gonad system and hierarchical status of hamadryas baboon males in an isolated group was studied. It has been established that the level of testosterone was higher in males occupying the leading position in a separate subgroup. A high level of sexual hormone was observed in animals with greater muscular mass and age. No correlation between hierarchical status and luteinizing hormone blood content has been observed in baboon males.

[Circadian rhythms of androgen levels in the blood of male hamadryas baboons]. / Tsirkadnye ritmy soderzhaniia androgenov v plazme krovi samtsov pavianov gamadrilov.

Radioimmunoassay was used to investigate circadian rhythms of blood plasma testosterone, 5 alpha-dihydrotestosterone, androstendione and dehydroepiandrosterone in intact animals and in those preadapted for experimental conditions. Blood plasma of monkey demonstrated monophasic circadian rhythms in the levels of androstendione, dehydroepiandrosterone and 5 alpha-dihydrotestosterone, with the maximal values seen early in the morning and minimal values in the evening. Circadian rhythms of testosterone were opposite in character. The adaptation of monkeys for housing and experimental conditions was marked by an increase in testosterone and 5 alpha-dihydrotestosterone levels in the blood as well as by an insignificant elevation of the levels of androgens of adrenal origin, leading to the changes in circadian rhythms of steroid hormones.

[Plasma corticosteroid level in male hamadryas baboons in various seasons of the year]. / Soderzhanie kortikosteroidov v plazme krovi samtsov pavianov gamadrilov na protiazhenii goda.

The levels of hydrocortisone, 11-deoxycortisole, 17-hydroxypregnenolone, 17-hydroxyprogesterone, 20-dihydroprogesterone, pregnenolone and progesterone were measured in blood plasma of adult male hamadryas baboons within a year using radioimmunoassay. Seasonal fluctuations characterized by the highest content of corticosteroids in spring-summer period and a considerable decrease of their concentration in autumn months have been revealed.

[Characteristics of the relationship between the circadian rhythm of the concentrations of corticosteroids and their precursors in the blood of baboon hamadryas and the initial functional state of the pituitary-adrenal cortex system]. / Kharakteristika tsirkadnykh ritmov soderzhaniia kortikosteroidov i ikh predshestvennikov v krovi pavianov gamadrilov v zavisimosti ot iskhodnogo funktsional'nogo sostoianiia sistema gipofiza--kora nadpochechnikov.

The occurrence of a single-phase circadian rhythm in the content of cortisole, 11-deoxycortisole, 17-hydroxypregnenolone, 17-hydroxyprogesterone, pregnenolone and progesterone in the blood plasma of hamadryas baboons was established by radioimmunoassay with peak levels early in the morning and minimum ones in the evening. The time course of changes in aldosterone levels in the intact animals significantly differs from that in the adapted ones. The maintenance of animals under other ecological conditions results in the decreased levels of all steroids studied and in significant changes in circadian rhythms of the content of cortisol precursors.

[Age differences in the hormonal reaction of the adrenals and testes to stress exposure in monkeys]. / Vozrastmye razlichiia gormonal'noi reaktsii nadpochechnikov i semennikov na stressornoe vozdeistvie u obez'ian.

Function of the adrenals and testes in immature and adult male baboons was studied in immobilization stress conditions. Concentrations of testosterone, 5d-dihydrotestosterone, hydrocortisone and precursors (progesterone, pregnenolone, 17-hydroxyprogesterone, 17-hydroxypregnenolone and 11-deoxycortisol) were determined in peripheral blood plasma by radioimmunoassay. It was shown that the main age-specific differences in hormonal reaction to stress are an unchanged level of androgens in the blood of immature animals and less marked increase in the level of hydrocortisone as compared to adult monkeys. The content of steroid precursors in the blood of immature monkeys diminished significantly in stressful conditions while in adult monkeys the level of the precursors was 3-5 times as increased.

Effect of stress on the profile of plasma steroids in baboons (Papio hamadryas).

Adult baboons (5 males and 5 females) were exposed to immobilization stress by being strapped to a table in a horizontal position for 2 h. In females the experiment was performed during both the follicular and luteal phase. Peripheral blood was withdrawn at frequent intervals, the first sample just before immobilization, and the last one 3 days later. A number of steroids were measured in blood plasma samples by radioimmunoassay (17-hydroxypregnenolone, 17-hydroxyprogesterone, pregnenolone, testosterone, dihydrotestosterone, progesterone, 20alpha-dihydroprogesterone, oestone, oestradiol) or competitive protein binding (cortisol) techniques. The cortisol levels exhibited a marked increase in both sexes. This increase was observed already during the immobilization and lasted for approximately 24 h. A similar, even more pronounced increase was seen in 17-hydroxypregnenolone, 17-hydroxyprogesterone and pregnenolone levels. A marked, long-lasting (72 h) decrease of testosterone and dihydrotestosterone levels was a consistent finding in male baboons. This was not observed in the females which, on the other hand, exhibited a marked decrease (duration 48 h) of progesterone and 20alpha-dihydroprogesterone levels during the luteal phase, and a significant decrease (duration greater than 24 h) of oestradiol and oestrone concentrations during the follicular phase. It is concluded that stress has a marked inhibitory action on gonadal function both in male and female baboons. In females and inhibition of steroidogenetic function is exerted both on the ovarian follicles and on the corpus luteum.

[Nature of changes in the level of steroid hormones and their precursors in peripheral blood of Papio monkeys under stress]. / Kharakter izmeneniia urovnia steroidnykh gormonov i ikh predshestvennikov v perifericheskoi krovi pavianov gamadrilov v usloviiakh stressa.

The radioimmunological method was applied to determination of changes in the peripheral blood plasma level of 12 steroids in male Papio hamadryas under immobilization and surgical stress. Androgen content decreased, and the concentration of steroid hormone precursors and hydrocortisone blood plasma content rose in response to stress. These changes were in contraphase with the circadian steroid rhythms. The most objective and sensitive criteria of the stress situation evaluation were decrease of testosterone and dihydrotestosterone level, increase of pregnenolone concentration, as well as of 17-alpha-hydroxypregnenolone, 17alpha-hydroxyprogesterone in the blood plasma.