[Direct and chemosignal-mediated effects of immune activation on behavior, glucocorticoid level, and body temperature in male mice during social conflict].

Behavioral and physiological effects mediated by immune system activation response to the injection of sheep red blood cells (SRBC) have been established to be mediated by chemosignal modification to a considerable extent while conducting experiments on BALB/cLac and C57B1/6j male mice. Control mice of both strains have been characterized by the same increase in plasma coricosterone concentrations caused by territorial conflict between the control and SRBC-treated males; hence, the quality of bedding did not have an effect on hormonal response. The greatest level of plasma corticosterone in SRBC-treated mice was detected after dyadic tests of social conflict in the case of provided bedding from the control mice. The bedding odor also determined the agonistic behavior of more aggressive male BALB/cLac mice. Dyadic tests staged on bedding in SRBC-treated males led to a decrease in the amount of direct aggression in comparison to tests on bedding in control males; moreover, the number of aggressive demonstrations positively correlated with the increase in the rectal temperature, which might be considered a manifestation of the emotional reaction to territorial conflict.

[Long-term dynamic of fecal corticosterone and its ecological and social correlates in males of great gerbil (Rhombomys opimus Licht.). Non-invasive approach in studies of stress in natural populations].

The relationship between fecal corticosterone concentrations and characteristics of the environment and population demography were studied in adult male gerbils (Rhombomys opimus Licht.) at the southern border of Kyzylkum desert (Reserve "Ecocentre Dzeiran", Bukhara region, Republic Uzbekistan) in spring and fall seasons from 1999 to 2004. We extracted hormones from air-dried fecal samples and analyzed their concentrations by radioimmunoassay (Gerlinskaya et al., 1993). An analysis for year-specific relationships between hormone concentrations and environmental variables of temperature and precipitation using Pearson's r statistic revealed that corticosterone concentrations correlated positively with total precipitation in January and February and negatively with precipitation during March and April. There was also a significant negative relationship between fecal corticosterone and the number of hot days in March (>20 degrees C). Demographic variables that characterized population densities (percent of burrow systems occupied, mean and maximum number of burrow systems/1 ha, number of females in the burrow system) correlated positively with corticosterone concentrations in feces in the beginning of spring, but these relationships were small compared with mean concentrations of corticosterone for the entire spring season that were strongly and positively correlated with number of gerbils, including all pups emerged, in burrow systems owned by one male (within its home range). In contrast, correlation coefficients of corticosterone concentrations with characteristics of feeding resources in the spring were low and negative. In the long-term perspective (interannual comparison), mortality among adult males was highly negatively correlated with mean corticosterone concentrations in the beginning of spring, which is within the period of maximum reproductive effort and potential stress. Body mass was independent of corticosterone concentrations in males in either the beginning of spring, or during the whole spring. In the fall, mean concentrations of fecal corticosterone in males was positively correlated with the number of days from June to October with mean daily temperatures exceeding 30 degrees C, and with percent of burrow systems where at least one adult, > or = 1 year old gerbil had survived. Mortality from fall to spring of the next year and the fall body mass did not correlate with concentrations of corticosterone in feces collected in the fall. When we analyzed corticosterone concentrations in spring seasons of all years combined using a stepwise regression analysis of a sampling of individual males (we analyzed residuals after withdrawal of year effect) on a set of variables representing habitat resources, distances between nearest neighbor males, and variables representing group demography we found low R2 values not exceeding 0.17. Within the six-year period, concentrations of corticosterone in the spring related negatively with abundance of annual herbs and positively with number of females in a male's social group. When only years of high density were analyzed, fecal corticosterone concentrations in males in the spring were again negatively determined by abundance of herbs, as well as by the nearest neighbor distance, and positively determined by the number of females within a male's home range. At the beginning of spring the only determinants were distance to the nearest neighbor male and number of females. In years of low density none of the variables were found to affect corticosterone levels during the whole spring, while in the beginning of spring only partial regression coefficients of abundance of herbs were negative and significant. Stepwise logistic regression analysis revealed positive dependence (P = 0.05) of disappearance of adult males during summer drought on concentrations of fecal corticosterone in the spring, but only when burrow systems with at least one adult (male or female) surviving after the summer were considered. Our results provide evidence ground for the assumption that in a desert rodent with non-regular population fluctuations such as the great gerbil, density may be more suppressed by external factors and not by density dependent mortality mediated by stress. Density dependent increases of stress caused by intense reproductive effort occurred when feeding and climatic conditions were favorable to compensate for negative effects on survival. However, in individual gerbils mortality mediated by stress can take place because we found higher stress in the beginning of spring in males, which did not occur in the population after the summer drought.

[Scent attractiveness and endocrine status in male students before and during a stress situation].

Scent attractiveness of sweat samples collected from male students before and during theoretical exams was assessed by female students. Five-rank scale was used for subjective assessment of the scent samples in term unpleasant/pleasant. Scent attractiveness depended on physiological conditions of both recipients and donors. Male students with low basal concentration of salivary cortisol smelt better than students with high level of cortisol. High level of salivary testosterone also was associated with low scent attractiveness of the male students, but only for the recipients in non-receptive phase of menstrual cycle. In all, the females who were in receptive phase of menstrual cycle assessed scent attractiveness of male students higher then the females in non-receptive phase. Exam stress coincided with increase of the salivary cortisol resulting in decline of scent attractiveness in male students. The negative effect of exam was most prominent in students that failed exam and in student who aspired to be the best but failed. So, the exam stress and basal variation of stress-related physiological indexes, such as salivary cortisol, are mirrored in male chemical signals, which are recognized by females.

[Effect of habitat type and population density on the stress level of midday gerbils (Meriones meridianus Pall.) in free-living populations]. / Viianie tipa mestoobitaniia i plotnosti naseleniia na stressirovannost' peschanok (Meriones meridianus Pall.) v svobodnozhivushchikh populiatsiiakh.

New methods of noninvasive evaluation of the endocrine status of animals by the content of hormones in feces were used to study the relationship between the stress level and social (population density) and ecological (habitat integrity) indices in natural populations of midday gerbil in the Southern Kalmykia in 2000. Stress level proved to increase with habitat disturbance but did not depend on population density of animals. The obtained data are discussed in the context of species-specific ecology and social behavior of midday gerbils.

[Social environment and morpho-physiological status of young males in the fall groups of great gerbil (Rhombomys opimus Licht). Effect of adults' presence]. / Sotsial'naia sreda i morfofiziologicheskii status molodykh samtsov v osennikh gruppakh bol'shoi peschanki (Rhombomys opimus Licht). Effekt prisutstviia vzroslykh osobei.

The dependence of stress and sex hormone levels, size of mid-ventral skin gland, and body mass of young males on the presence in social groups of adult gerbils (>1 year old) were studied during the fall of 1999 in the non-breeding high density population of the great gerbil (Rhombomys opimus Licht; Bukhara region, Uzbekistan). Contents of corticosterone and testosterone in fecal samples collected from young males in the field were analyzed by non-invasive radioimmunoassay. The fall gerbil groups with adults were of larger size than those without adults. The total number of individuals in a group is positively correlated with concentration of corticosterone in feces of young males. Presence of adult male and especially of adult female suppresses maturation of juvenile males indicated by size of the androgene-dependent mid-ventral gland, but accelerates their total growth. Thus, the social environment influences morpho-physiological characters of young males, effecting rate of their maturation directly or indirectly through the density dependent stress.

[Changes in glycolysis and glycogenolysis in tissues and level of certain hormones in blood and urine from rats with varying lengths of cold adaptation]. / Izmenenie glikoliza i glikogenoliza v tkaniakh i soderzhanie nekotorykhgormonov v krovi i moche u krys v razlichnye sroki kholodovoi adaptatsii.

The production phase changes of adaptive hormones and the activity of key glycolytic and glycogenolytic enzymes were studied in Wistar rats exposed to a long-term (1-49 day) cold (+5 degrees C) exposure. The allosteric mechanisms responsible for regulating carbohydrate metabolism were shown to interact with endocrine ones and to modulate their effects. In cold acclimation, activation of the sympathoadrenal system aimed not only at increasing carbohydrate metabolism, but at enhancing the metabolism of fats and calorigenic effects.

[Effect of diet on the biochemical parameters of blood in the population of the Asian North]. / Vliianie pitaniia na biokhimicheskie pokazateli krovi u zhitelei Aziatskogo Cevera.

The studies have shown that the diet of the native residents of Taimyr is imbalanced of the major nutrients (high uptake of carbohydrates and low uptake of fats and proteins). A certain correlation has been found between the higher incidence rates of coronary heart disease, blood atherogenic lipoprotein levels and changed diet pattern.

[Effect of blood serum hormones and lipoproteins on levels of cAMP and cGMP in viable sections of rat liver]. / Vliianie gormonov i lipoproteidov syvorotki krovi na soderzhanie tsAMF i tsGMF v perezhivaiushchikh srezakh pecheni krys.

Cyclic nucleotides are universal intermediary agents of hormones in the target tissues, however mechanisms of the regulation of the cAMP and cGMP content in the cell are rather complex and still obscure. More data have appeared of late on the involvement of blood serum lipoproteins in the regulation of various intracellular processes including adenylate cyclase activity. Therefore the purpose of the study was to investigate the effect of adrenaline, hydrocortisone, glucagon, insulin and blood serum lipoproteins on the cAMP and cGMP content in rat liver surviving sections. An attempt was made to study a cooperative effect of the above hormones and lipoproteins of various classes. The results obtained have shown that adrenaline and glucagon raise the cAMP level in rat liver surviving sections. The effect of adrenaline is mediated by beta-adrenoreceptors. Insulin lowers an increases the level of cAMP in liver sections determined by the effect of glucagon. A decrease of the initial cAMP content in response to insulin occurs after a short lag period. High density lipoproteins (HDLP3) reduce the cAMP content in liver surviving sections. A cooperative effect of lipoproteins of a very low density and adrenaline (or hydrocortisone) in the regulation of the cAMP content in the rat liver was revealed. The cGMP content in rat liver surviving sections does not change under the influence of the above hormones and lipoproteins.

[Change in the activity of the key gluconeogenesis enzymes in the rat liver and kidneys during the action of subextreme and extreme factors on the body]. / Izmenenie aktivnosti kliuchevykh fermentov glikoneogeneza v pecheni i pochkakh krys pri deistvii na organizm subékstremal'nykh i ékstremal'nykh faktorov.

The activity of glucogenesis key enzymes (phosphoenolpyruvate carboxinase, fructoso-1,6-siphosphatase, glucoso-6-phosphatase) of the rat liver and kidneys was studied simultaneously under the effect of extreme and subextreme factors on the organism. The low initial phosphoenolpyruvate carboxikinase activity in the liver and its high inductivity under extreme conditions suggest a role of this enzyme as limiting link in glyconeogenesis. The activity of phosphoenolpyruvate carboxinase in the kidneys is comparable to that of fructoso-1,6-diphosphatase; it is considerably higher than the activity of glucoso-6-phosphatase. The phosphoenolpyruvate carboxinase activity in the kidneys is 5--6 times higher than in the liver. The activity of phosphoenolpyruvate carboxinase and glucoso-6-phosphatase is increased under the effect of extreme factors, and that of fructoso-1,6-diphosphatase remains unchanged. The lack of clear synchronous changes in the activity of glucogenesis key enzymes in the liver and kidneys indicates that the cells of these organs do not provide the united operon for phosphoenolpyruvate carboxinase, fructoso-1,6-diphosphatase and glucoso-6-phosphatase with common regulation mechanism.