[The physiological characteristics of genetic predisposition to catalepsy in rats depending on the stage of selection]. / Nekotorye fiziologicheskie kharakteristiki geneticheskoi predraspolozhennosti k katalepsii u krys v zavisimosti ot stadii selektsii.

Male rats with a genetic predisposition to cataleptic reactions revealed a reduced motor activity and a diminished activation of mineralocorticoid and testosterone synthesis in response to a mild stress as compared with the Wistar rats. The reactions, however, were exactly opposite in the Wistar rats with signs of cataleptic features. The data obtained suggest that, when creating genetic animal models of human diseases, the initial stages of breeding should correspond to early stages of the disease whereas advanced stages of breeding are similar to later, chronic phases of the disease.

[The sex and corticosteroid hormones of rats selected for estrous-cycle reaction to constant illumination]. / Polovye i kortikosteroidnye gormony krys, selektsionirovannykh po reaktsii éstral'nogo tsikla na postoiannoe osveshchenie.

Two substrains of rats selected for the high (ESTH) and low (ESTL) ability to develop permanent oestrus under constant illumination were produced. The concentration of estradiol, testosterone in blood and 11-OCS in blood and adrenals was studied in rats of the 29 th generation under normal day (14L : 10D) and constant illumination (CL). The concentration of estradiol in blood of control rats in proestrus was 61.6 +/- 4.1 pg/ml and did not differ from substrain ESTH (59.6 +/- 4.5 pg/ml) and ESTL (58.8 +/- 4.8 pg/ml); in oestrus, the minimal concentration of estradiol was noted in control-(46.5 +/- 3.1 pg/ml), maximal one-in rats of substrain ESTL (63.3 +/- 6.2 pg/ml), in ESTH-55.8 +/- 1.7 pg/ml. The maintenance of rats in condition of CL brought about the tendency to decrease the level of estradiol in blood of rats selected in proestrus and to increase it in oestrus in comparison to control. The level of testosterone in blood of control rats in proestrus-oestrus changed in parallel to concentration of estradiol. The concentration of testosterone in blood of selected rats was higher in proestrus-oestrus as compared to control. In condition of CL, the testosterone level in proestrus did not differ from control, in oestrus it was higher than in control. The level of 11-OCS in adrenals of selected substrain was higher than in control as well in condition of 14L : 10D as in CL. The exception was substrain ESTH-in proestrus the concentration of 11-OCS in condition of CL was lower than in control. CL drastically changed direction of cyclic shifts in level of 11-OCS from higher value in proestrus under condition of 14L : 10D to low one in condition of CL. The fluctuation of 11-OCS level in blood in groups of experimental rats usually was parallel to that in adrenals.

[The neurohormonal characteristics of rats selected for the duration of the passive defense reaction and for the threshold of neuromuscular excitability]. / Neirogormonal'nye kharakteristiki krys, selektsionirovannykh po dlitel'nosti passivno-oboronitel'noi reaktsii i porogu nervno-myshechnoi vozbudimosti.

Two strains of rats, "genetic catalepsy" and "low-threshold", simulating some human psychopathological symptoms, were compared. Levels of brain monoamines and blood corticosterone and testosterone showed no common features in the strains studied. The levels of dopamine in amygdala and testosterone blood levels in rats of the two strains significantly deviated in opposite directions from corresponding controls. In "genetic catalepsy" strain noradrenaline content in striatum and diencephalon was decreased, and serotonin striatal level was increased.

[The circadian rhythm of the adrenal glucocorticoid function in female rats selected for the reaction of the estrous cycle to constant illumination]. / Sutochnyi ritm gliukokortikoidnoi funktsii nadpochechnikov samok krys, selektsionirovannykh po reaktsii éstral'nogo tsikla k postoiannomu osveshcheniiu.

Studies have been made of the circadian rhythms of a glucorticoid hormone, corticosterone, in the adrenals and blood serum in female Wistar rats from two substrains selected for high (ESTH) and low (ESTL) ability to develop permanent oestrus under constant illumination. Significant changes in parameters of the circadian rhythm of the hormone were observed in animals of the 26th generation of selection. Total alleviation of corticosterone rhythm in the blood was on observed in ESTL rats, while in ESTH animals maximum level of the hormone in the blood was shifted to the dark time. Comparison of a high corticosterone content of the adrenals in ESTL rats with a low concentration in the blood plasma indicates the increase in metabolic clearance of the hormone in animals from this strain. It is suggested that the decreased corticosteroid production in the adrenals of ESTH rats facilitates the development of permanent oestrus under constant illumination.

[Biosynthesis of corticosteroid hormones in the cortical areas of the rat adrenal during emotional stress combined with a salt load]. / Biosintez kortikosteroidnykh gormonov v zonakh kory nadpochechnikov krys pri émotsional'nom stresse v sochetanii s solevoi nagruzkoi.

The experiments on male albino rats have shown that excessive salt uptake increases the functional sensitivity of the adrenal cortex to emotional stress (group fighting). Emotional stress in combination with a salt load induces a much greater increment in corticosterone and 18-oxy-11-deoxycorticosterone production by fascicular and glomerular adrenal zones through the activation of the pregnenolone pathway of hormonal biosynthesis. A relatively high aldosterone production was also retained. Thus, the total mineralocorticoid potential directed to sodium retention in the body is in these conditions inadequately increased.

[Effect of an antidiuretic hormone on the aldosterone level in the blood plasma of rats with chronic water load and limited sodium intake]. / Vliianie antidiureticheskogo gormona na uroven' al'dosterona v plazme krovi krys s khronicheskoi vodnoi nagruzkoi i ogranicheniem potrebleniia natriia.

The concentration of aldosterone in blood plasma of rats with chronic water and restricted sodium chloride intake substantially rose after subcutaneous injection of the antidiuretic hormone pituitrin in physiological doses. No simultaneous increase in blood corticosterone was seen. The production of hormones by rat adrenals remained unchanged. The results of experiments made with ACTH alone or combined with pituitrin permitted the conclusion that the increase in aldosterone concentration was not linked with a possible stimulation of endogenous ACTH secretion. The augmentation of aldosterone concentration in the peripheral blood of rats with chronic water intake induced by pituitrin is likely to be due to a decrease in metabolic clearance of the hormone.

[Adrenal mineralocorticoid function in sodium deficit with adequate or excess water consumption]. / Sostoianie mineralokortikoidnoi funktsii nadpochechnikov pri natrievom defitsite s adkvatnym ili izbytochnym potrebleniem vody.

Upon addition of 3H-progesterone to the incubation medium the in vitro aldosterone production by the capsular part of the adrenals increased in rats exposed to two-week restriction of sodium intake, while that of deoxycorticosterone and corticosterone declined. The specific activity of corticosteroids appreciably rose which could suggest a decrease in the intensity of pregnenolone production in the early stage of the biosynthesis. The peripheral plasma aldosterone level increased considerably. During sodium restriction and excess water intake the biosynthesis of aldosterone remained unchanged whereas its blood concentration did not rise. The excess water intake with sodium restriction is supposed to reinforce the metabolic clearance of aldosterone.

[Corticosteroid biosynthesis in various water-salt dietary regimens]. / Biosintez kortikosteroidnykh gormonov nadpochechnikami pri razlichnykh vodno-solevykh rezhimakh pitaniia.

The production of desoxycorticosterone, 18-hydroxy-desoxycorticosterone and corticosterone by the mouse adrenals increases in vitro whereas 18-hydroxy-corticosterone and/or aldosterone production falls to an uncertain level when the salt consumption rises from about 0.07 to 50 mekv per animal a day under conditions of water consumption ad libitum. Specific activity values of 3H-corticosteroids, being formed by the adrenal cortex capsule from 3H-progesterone, added to the incubated culture, decrease. Aldosterone production by the adrenals remains unchanged under conditions of sodium load with the limited water consumption. It is suggested that the stimulating effect of endogenous ACTH on the adrenal cortex is potentiated because of the increased salt consumption.

[Functional activity of the adrenal cortex and thymus of mice of strains AKR, C57BL/6, C3H/He and C3Hf]. / Funktsional'naia aktivnost' kory nadpochechnikov i massa timusa u myshei linii AKR, C57BL/6, C3H/He and C3Hf.

The authors studied the relationship between the functional activity of the adrenal cortex before and after the ACTH administration and the thymus mass in AKR, C57BL/6, C3H/He, and C3Hf mice. Blood 11-OCS level of these mice proved to differ in accordance with the differences in the 11-OCS production by the adrenal glands. There was revealed no expected inverse correlative dependence between the basal blood glucocorticoid content and the thymus mass. After ACTH administration the mouse species could be placed thus in order of increasing reaction of the thymus: AKR less than C3Hf less than C3H/He less than C57BL/6; this correlated positively with the level of 11-OCS production by the adrenal glands and basal 11-OCS concentration in the peripheral blood.

[Distribution of mineralocorticoid receptors in the kidney cells of rats with different levels of aldosterone in their bodies]. / Raspredelenie mineralokortikoidnykh retseptorov v kletkakh pochek krys pri razlichnykh urovniiakh soderzhaniia al'dosterona

A metabolic method was applied to the study of the distribution of mineralocorticoid receptors in the kidney cells of rats at various aldosterone levels in the organism. A great number of binding sites of aldosterone in the cytoplasm and a low aldosterone-H3 binding by the nuclei of kidney cells was revealed in adrenalectomized rats, as well as in the animals kept under conditions of sodium load, when endogenous aldosterone was absent in the organism. A reduction of the number of binding sites in the cytoplasm and an increase of aldosterone-H3 binding in the nuclei was noted in the animals with a high content of the given hormone in the organism (sodium deficiency in food or aldosterone administration to the adrenalectomized animals). The difference in the hormone binding by the nuclei of the kidney cells of rats kept under conditions of sodium loading or deficiency corresponded to an even greater difference in the aldosterone binding by the chromatin proteins of such nuclei. It is supposed that an increased aldosterone concentration in the organism intensified the change from the cytoplasm and the accumulation of specific aldosterone-receptor complexes in the nuclei.

[Binding of H3-aldosterone to cytoplasmic receptors of the kidney in various functional states of the organ target]. / Sviazyvanie H3-al'dosterona s tsitoplaszmaticheskimi retseptorami pochki pri razlichnykh funktsional'nykh sostoianiiakh organa-misheni

A study was made of the capacity of the cytoplasmic cell fraction of rat kidney to bind H3-aldosterone, depending on the level of Na uptake with food, and, consequently, on the intensity of aldosterone secretion by the adrenal glands. It was shown by Sketchard's method that there existed in the cytoplasmic fraction of the kidney cells of rats with a high and low level of aldosterone secretion two classes of receptors binding aldosterone with a different degree of affinity. The number of binding sites for aldosterone in the 1st class of receptors, more specific for mineralocorticoids in the animals with a low level of aldosterone secretion (Na loading), was double that in comparison with the animals with a high level of aldosterone (Na deficiency). It is supposed that an increased aldosterone concentration in the organism in Na deficiency increased the transport of the specific hormone-receptor complex from the cytoplasm into the nucleus.