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The aim of this study was to investigate time-related changes in substance P (SP) beta-endorphin (BE), and corticosteron (CORT) levels induced by DSIP administration in rats subjected to emotional stress. Experiments were carried out in male Wistar and August rats with different resistance to emotional stress. At night rats were tied by their tails to the backside of the special cages. These stress-inducing procedure was repeated for 12 hours daily in the course of 5 days. SP and BE immunoreactivity in the hypothalamus and plasma and blood CORT level were determined radioimmunologically. Six groups of animals were formed: 1. control animals; 2. stressed animals; 3. rats which received DSIP in a dose of 60 nmol/kg one hour before decapitation; 3. rats to which DSIP was injected 24 hours before decapitation; 5. stressed rats to which DSIP was injected one hour before decapitation during the 5th exposure to stress; 6. stressed rats to which DSIP was injected 12 hours before the 5th exposure to stress, i.e. 24 hours before decapitation. Our experiments showed that DSIP administration induced marked changes in SP, BE, and CORT levels in the hypothalamus and blood plasma. This suggests that long-term stress-coping effects of DSIP in underlied by considerable changes in the content of other oligopeptides and hormones. Evidently, DSIP triggers these processes inducing a cascade of interrelated molecular reactions which are different in Wistar and August rats. It seems likely that DSIP administration stimulates the mechanisms of resistance in August rats to a lesser extent than in Wistar rats.

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The paper is devoted to study of the influence of short-term low-level microwave irradiation (6GHz, modulation 2 Hz, average intensity 0.015 mW/cm2, exposure time 50 min) on some electrophysiological and hormonal parameters in rabbits. No reliable changes in cardiac and respiratory rhythms, electromyogram intensity as well as cortisol, testosterone, insulin and thyroxine level in rabbits' blood were found.

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In male rats of Wistar strain individual nociceptive sensitivity properties were studied in correlation with steroid hormones level in the plasma. Seven groups of experimental animals were observed remarkable for dynamics of nociceptive sensitivity. Repeatedly applied test painful stimuli caused reliable changes of corticosterone and testosterone level in the plasma. Individual differences were found of the level of steroid hormones in the plasma in rats from different groups.

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Angiotensin-converting enzyme (ACE) activity in serum and some brain areas, level of angiotensin I in the blood and drinking behaviour during immunization of rats against conjugate of angiotensin II with bovine serum albumin (BSA) were studied. The results show that an increase in antibodies against angiotensin II was correlated with elevated ACE activity in serum. There was a distinct tendency towards elevated level of angiotensin I in the blood. After a 6 month's immunization ACE-activity was reduced twofold to threefold in midbrain and hypothalamus-thalamus. During immunization water-uptake was increased by 40-45%.

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Changes in dynamics of nociceptive sensitivity in male rats of Wistar strain were studied during formation of negative emotional reaction. The procedure of blood's taking from the tail after its tip's amputation was used as negative emotional factor. The animals were divided into six groups by the criterion of individual properties of nociceptive sensitivity dynamics. On the whole it was found to decrease. Besides, one more group (the seventh group) was found with profound hypoalgesia caused by action of the negative emotional factor. It was also shown that formation of negative emotional reaction in two groups was not accompanied by changes of nociception. The data suggest a selective influence of negative emotional factor on nociceptive sensitivity.

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Changes in nociceptive sensitivity and the level of steroid hormones (corticosterone and testosterone) in the plasma of male Wistar rats were studied in repeatedly applied painful stimuli. According to the changes in nociceptive sensitivity the animals were divided into 6 groups. A reliable corticosterone increment and testosterone decrement in the plasma were caused by repeatedly applied painful stimuli. The data observed could be used as individual indices characteristic of animals of this strain.

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Morphofunctional peculiarities of ovarian development in 1- and 4-day-old rats have been studied under conditions of their transplantation into mature female rats. In 30 days in transplants of both series of the experiments atretic process develops. Better preservation of the general pool of the germ cells and follicles is obtained at transplantation of the ovaries from the 4-day-old donors; their ovocytes at the operation time are at the stationary state of meiosis prophase. Ovocytes of 1-day-old animals, being at the stages of early prophase, are more vulnerable at homotransplantation.

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The influence of tongue deafferentation on the plasma level of sodium homeostasis-controlling hormones has been studied. Using radioimmunoassay, high corticosterone and aldosterone plasma levels were discovered in rats with tongue deafferentation, as compared to sham-operated controls. ACTH and angiotensin I plasma concentrations in deafferentated rats were the same as in sham-operated rats. The role of emotional factors of taste perception in sodium homeostasis control is being discussed.

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The experiments on cats and rabbits have studied electroencephalographic, endocrine and blood pressure responses to stress (5-hour immobilization with electrical foot shock) before and after coagulation of the midbrain nuclei raphe. Blood pressure and adrenal responses in advanced (4-hour) stress were elevated in intact animals, the responses attenuating after coagulation of the nuclei raphe. Background bioelectrical activity of the midbrain reticular formation and hypothalamus was found to be activated in the operated animals. Stress was followed by the reduction in bioelectrical changes of the above subcortical structures with the parallel development of "burst" activity in the dorsal hippocamp.

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Radioimmunoassays were employed to study variation in the concentration of corticosterone, ACTH and beta-endorphin in rat blood plasma at different times of the 30-hour immobilization and under the effect of a short-term action of ecologically significant negative stimulation emanating from other animals. Both prolonged immobilization stress and short-term emotional reaction produced appreciable alterations in the blood plasma content of all the hormones under study. The findings indicate that variations in the corticosterone and beta-endorphin levels were in the best agreement.

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A study was made of the effect of chronic emotional stress on the formation of hypertension in animals. This was shown to be related to dynamic changes in the function of the CNS, particularly in the hypothalamic apparatus of the neuroendocrine control. The above changes played a role in the formation of hypertensive vascular reactions accompanied by a high hormonal secretion of the adrenal cortex and thyroid. During stabilization of high arterial blood pressure at the late stages of the "after-effect", the hormonal secretion returns to normal.

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A great amount of different problems on morphogenesis and histophysiology of the corpus luteum is presented, with an emphasis on light optic and ultrastructural data that characterize the developmental dynamics of the corpus luteum. The vascular reaction is described in details, beginning from the preovulatory period. The total high vascularization rate is demonstrated and certain information on ultrastructure of newly formed capillaries and macrophages is concerned with. For the first time the authors' data on intravascular macrophages are given. The role of macrophages in the function and structural dynamics of the corpus luteum is discussed. Owing to the results obtained histochemically, ultrastructurally and biochemically, the subject on dynamics of the corpus luteum hormonoproduction, on processes participating in the hormone secretion, as well as on the role of the interstitial tissue in the corpus luteum formation is considered. The data from the literature and those of the authors are presented concerning the means and ways of progesteron transport in the form of vesicles, granules, or by means of molecular diffusion. Participation of the corpus luteum macrophages (tissue and vascular ones) in processes of synthesis and transport of progesteron is analysed. The role of prostaglandins in the chain of regulation of development, function and involution of the corpus luteum is studied. The changes in balance of prostaglandins, when prostaglandin F2 is administered result in decreasing amount of progesterone in blood. In the experiment, synthesis of prostaglandins is blocked by indometacin administration and it causes certain disturbances in luteal transformation.

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A study was made of the effect of prostaglandin F2 alpha on submicroscopic and histochemical structure of the yellow bodies and progesterone concentration in peripheral blood plasma in the pre-implantation period of embryonal development. Electron microscopy, radioimmunoassay and histochemical technique were applied. Apart from the signs of steroidogenesis preservation in luteocytes of the control group yellow bodies (during elevation of prostaglandin F2 alpha concentration in the body), there was a significant reduction of the activity in them of the key enzyme of the steroidogenesis, 3-beta-steroid dehydrogenase. Attention is paid to variation of the capillary system of the yellow bodies, induced by prostaglandin F2 alpha. This variation was marked by the absence of fenestration and by reactive status of endotheliocytes. It is concluded that prostaglandin F2 alpha primarily affects functional properties of steroid-producing cells. The authors suggest that there are potential links between the reduced progesterone level in peripheral blood plasma and submicroscopic changes in luteic cells and yellow body capillaries.

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By means of radioimmunoassay, 17 beta-estradiol-, androgen- (testosterone and dihydrotestosterone) and progesterone contents were determined in the peripheral blood of the female sables, aged 2 to 27 months, during postnatal ontogenesis initial stage. Under the action of seasonal factors steroid level was sharply decreased in the animals of the all ages within the autumnal period, whereas the gonadal function activation lowered over a period of February and March, when "the spring animation" of wild stables is seen. An increase in the sex hormone level was more pronounced in females over one year old. The compared concentrations of hormones, studied in the 5-months' females (the growth stopping). 14 to 17-months' animals (the 1st year reproductive period) and 27-months' stables (the 2nd year reproductive period) were close to those of 17 beta-estradiol and progesterone contents in fertile animals. It is suggested that the sexual system of the 5-months' females is ready for the reproductive processes but their secretory activity is sharply reduced, probably under the seasonal factor influence.

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Radioimmunological method was applied to the study of progesteron and 17 beta-estradiol profiles in the peripheral blood plasma of pregnant mice from the time of the zygote formation (the 1st day of gestation) to the blastocyst implantation (the 5th day of gestation). The peak of a progesteron concentration in the plasma and the onset of reduction in the 17 beta-estradiol concentration were noted in the evening of the 3rd day of pregnancy. From this period there was a fall in the 17 beta-estradiol and progesterone content in the blood plasma. In the evening of the 3rd day of pregnancy the 14-18-cell embryos passed from the oviduct into the uterine cornu. The role played by the embryo in changes of the maternal hormonal status is discussed.

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