Determination of seven unconjugated steroids in the blood and seminal plasma of the fertile male rabbit.

Seven unconjugated steroids were measured in the blood and seminal plasmas of fertile male rabbits by radioimmunoassay. The blood plasma testosterone concentration was 4--5 times that of the seminal plasma. Dehydroepiandrosterone, estrone and 17beta-estradiol were found in measurable amounts in the blood plasma; however, these steroid levels were slightly lower in seminal plasma. Androstenedione and 5alpha-dihydrotestosterone were present in equal quantities in both the seminal and blood plasmas. By contrast, seminal plasma pregnenolone level was about twice that of the blood plasma. The determination of seminal plasma steroids may lend itself as a complementary assessment to blood steroid determinations for the evaluation of the normal function of various reproductive organs.     

State of steroid secretory cells and concentration of gonadal steroid hormones in the blood plasma of Siberian sturgeon <Emphasis Type="Italic">Acipenser baerii</Emphasis> and sterlet <Emphasis Type="Italic">A. ruthenus</Emphasis> (Acipenseridae) during sex differentiation

Results of studying steroid secretory cells in gonads and the level of estradiol-17β and testosterone in the blood plasma of young Siberian sturgeon Acipenser baerii and sterlet A. ruthenus, aged 8.5 and 9.5 months, respectively, is studied. During sex differentiation, the steroid secretory activity in females is intensified first in the stroma of gonads and then, after the formation of oocytes during the previtellogenesis period, it is shifted to the follicle theca. The development of oocytes is accompanied by a decrease in the concentration of testosterone and an increase in the concentration of estradiol-17β. In males, the intensification of the activity of steroid secretory cells, which was indirectly determined by the state of organoids, is accompanied by an increase in the concentration of testosterone in blood plasma.     

Catecholamines in steroid-dependent brain development

Sex-specific peculiarities of catecholamine (CA) content and turnover in neuroendocrine brain areas and their modification with neonatal steroids or prenatal stress (PS) in Wistar rats were studied. No changes in noradrenaline (NA) content and turnover rate were found in the preoptic area (POA), meanwhile dopamine (DA) turnover rates in the POA and mediobasal hypothalamus (MBH) were increased in neonatally androgenized 10-day-old females. Treatment of female neonates with various catecholestrogens increased hypothalamic NA content by 30–95% but only 4-hydroxyestradiol-17β induced anovulation. 6-Hydroxydopamine had no significant impact on hypothalamic CA content in neonates and did not prevent testosterone-induced persistent estrous. Maternal stress (restriction for 1 h a day, 15–21st days of pregnancy) resulted in a decrease of hypothalamic NA and blood plasma corticosterone response to acute stress in adult male offspring. Sex differences in CA content in the POA and MBH disappeared in 10-day-old prenatally stressed rats. Conclusions: (1) sexual brain differentiation needs co-operative actions of sex steroids and CA to be completed; and (2) early changes in CA content and turnover induced by PS or neonatal steroid exposure predetermine long-term alterations of the stress responsiveness, reproductive behaviour and neuroendocrine control of ovulation.     

The relationship between homozygosity level and animal physiology: Iron content of plasma and whole blood as well as total iron binding capacity by transferrin (TIBC) in rats of various inbreeding coefficient

Male and female wild Norway rats (Rattus norvegicus Erxleben) and male and female albino outbred rats (Ipf:RIZ) were crossbred. These animals were the control, noninbred group (0% inbred). By systematic full-sib mating, two experimental groups (50 and 91% of inbred) were raised. Half of each group (both males and females) was exposed to physical stress (3 days of starvation and 3 hr of swimming). The other half of each group was ether anesthetized to collect blood. The iron content of plasma and whole blood, as well as the total iron binding capacity, was determined by the Atom-Spec method. A significant decrease in the iron content of plasma and whole blood as well as the TIBC was observed by an increase in the inbreeding coefficient. Stress significantly influenced the iron content of plasma and whole blood as well as the TIBC, whereas the sex of the rats affected the whole-blood iron concentration and TIBC. Moreover, some double interactions had an impact on the iron content and TIBC. The interactions were as follows: plasma—inbreeding level and stress; whole blood—sex and stress; and TIBC—inbreeding level and sex.     

Level of neuroactive steroids in the brain and sex-related peculiarities of formation and extinction of conditioned reflex in rats

Sex-related peculiarities of dynamics of brain sex steroids in the process of learning and extinction of the conditioned reflex of passive avoidance have been studied in model experiment. Prior to learning of the conditioned reflex, female rats were found to be distinguished by manifestation of anxiety and fear as compared with male rats. At formation of the conditioned reflex, no significant sex-related differences were detected between males and females, whereas extinction of the conditioned reaction of passive avoidance in males occurred by 2–3 days faster than in females. At learning of conditioned reaction of passive avoidance, in sexually mature male rats there was revealed an increase of the testosterone content in various brain structures, especially in hippocampus and frontal cortex, while its level in blood plasma remained unchanged. Also shown was an elevation of estradiol concentration in female amygdale, whereas at extinction of the conditioned reaction of passive avoidance, a rise of estradiol values was noted in hippocampus and cingular cortex. At the same time, the testosterone level in blood plasma did not change, whereas after extinction of the conditioned reflex the estradiol concentration decreased statistically significantly. Different dynamics of changes of the sex steroid levels in brain and blood plasma can indicate a possibility of their formation in the nervous tissue. The performed correlation analysis confirms the concept of selective involvement of testosterone and estradiol of individual brain structures in realization of processes of learning and memory in sexually mature male and female rats.     

Haematological effects of stress on a teleost, Esox lucius L.

Stress produces a haemoconcentration, elevated blood lactate, increased glucose concentrations and alters the plasma electrolyte balance in two groups (brackish- and freshwater) of the northern pike, Esox leucius L., after one month's starvation. A method for dorsal aorta catheterization and a receptacle for cannulating fish is described.
The blood glucose level of the freshwater pike was twice that of the brackish-water group, and the plasma sodium and magnesium concentrations in the brackish-water pike were significantly higher. The haematocrit, haemoglobin and blood lactic acid concentrations were higher in freshwater pike. The plasma potassium and calcium concentrations in the two groups did not differ.
Haemoconcentration due to stress by handling for 1.5 min was shown by changes in haematocrit and haemoglobin values. The haemoglobin concentration returned to normal in freshwater pike after 4 h but in brackish-water pike after 12 h.
As a result of handling, the blood lactic acid level rose steeply and required 12 h to return to normal.
The blood glucose concentration rose to its maximum value within 1 h of handling and required two days to return to normal.
The plasma sodium level remained stable after handling, but the potassium level was erratic. In brackish-water, the potassium concentration of the pike remained high for 12 h after stress, but in the freshwater group, after a rise, the concentration fell to below the initial level within 4 h. The changes of the potassium concentrations in relation to sampling time are discussed. The changes in the divalent ion concentrations were marked and similar in the two groups; with an increase lasting 1–4 h and then a fall below the initial level, which was regained after two days.     

Hormonal and immunological changes in blood and mammary secretion in the sow at parturition

The purpose of the present study was to record possible variations of estradiol-17 beta (E2) and cortisol concentrations, and parameters related to granulocyte phagocytosis in mammary secretions from healthy sows at parturition. The study was comprised 8 primiparous sows (Landrace x Yorkshire). Blood and mammary secretion samples were collected twice daily from 3 d before (only blood) until 3 d after farrowing. Estradiol-17 beta and cortisol concentrations were determined in plasma and in cell-depleted skimmed mammary secretions. Phagocytic capacity of polymorphonuclear cells (PMN) was assessed in whole blood and in cell suspensions derived from mammary secretions. Opsonic activity was assessed in serum and in cell-depleted skimmed mammary secretions. The 2 assays were based on chemiluminescence. Estradiol-17 beta concentration in plasma decreased (P < 0.001) directly after parturition. In skimmed secretions, the highest E2 concentration was recorded in the first sample after parturition and decreased (P < 0.01) thereafter. The highest cortisol concentration in plasma was recorded in the evening before parturition (P < 0.01). In skimmed secretions, there was no significant variation in cortisol concentration. The concentrations of both steroid hormones were lower in mammary secretions than in plasma. The phagocytic capacity of PMN in blood and mammary secretion, expressed as peak chemiluminescence per PMN, showed no significant change. This was also true for the opsonic activity in serum. In skimmed secretions the opsonic activity increased (P < 0.01) after parturition. These data emphasize the differences between plasma and mammary secretion concentrations of steroid hormones as well as between systemic and mammary gland immune competence. Regarding the phagocytosis process in mammary secretions, the part directly related to the PMN function seemed not to be altered at parturition compared with later on in lactation, whereas the part related to opsonic activity seemed to be impaired at parturition. The latter may play a role in the development of coliform mastitis at this time.     

Steroid concentrations in plasma, whole blood and brain: effects of saline perfusion to remove blood contamination from brain

The brain and other organs locally synthesize steroids. Local synthesis is suggested when steroid levels are higher in tissue than in the circulation. However, measurement of both circulating and tissue steroid levels are subject to methodological considerations. For example, plasma samples are commonly used to estimate circulating steroid levels in whole blood, but steroid levels in plasma and whole blood could differ. In addition, tissue steroid measurements might be affected by blood contamination, which can be addressed experimentally by using saline perfusion to remove blood. In Study 1, we measured corticosterone and testosterone (T) levels in zebra finch (Taeniopygia guttata) plasma, whole blood, and red blood cells (RBC). We also compared corticosterone in plasma, whole blood, and RBC at baseline and after 60 min restraint stress. In Study 2, we quantified corticosterone, dehydroepiandrosterone (DHEA), T, and 17β-estradiol (E₂) levels in the brains of sham-perfused or saline-perfused subjects. In Study 1, corticosterone and T concentrations were highest in plasma, significantly lower in whole blood, and lowest in RBC. In Study 2, saline perfusion unexpectedly increased corticosterone levels in the rostral telencephalon but not other regions. In contrast, saline perfusion decreased DHEA levels in caudal telencephalon and diencephalon. Saline perfusion also increased E₂ levels in caudal telencephalon. In summary, when comparing local and systemic steroid levels, the inclusion of whole blood samples should prove useful. Moreover, blood contamination has little or no effect on measurement of brain steroid levels, suggesting that saline perfusion is not necessary prior to brain collection. Indeed, saline perfusion itself may elevate and lower steroid concentrations in a rapid, region-specific manner.     

Acute emotional stress and cyclic nucleotide content of the heart and blood plasma

The relationships between the changes in arterial pressure and the content of cyclic nucleotides in the heart and blood plasma were studied on rabbits exposed to acute emotional stress. During 3 hours of the stress program, there were changes in arterial pressure, namely an elevation within the first hour followed by a progressive fall during subsequent 2 hours and death of the animals. The content of cAMP in the heart rose to a greater degree than that of cGMP. The content of cAMP in the blood plasma considerably increased, while the level of cGMP remained unchanged. The data obtained attest to the predominance of activation of adrenergic structures over activation of cholinergic structures.     

Effects of sampling on blood parameters in the rainbow trout, Salmo gairdneri Richardson

The effects of sampling and short-term storage of blood samples on the blood parameters of rainbow trout were evaluated by comparing values obtained from resting fish sampled via cannulae and from fish sampled by cardiac puncture. Sampling stress causes an increase in haematocrit value and a decrease in mean cellular haemoglobin concentration, indicating red cell swelling. These changes are aggravated by consecutive storage of samples. Also, blood ionic balance is affected. The K⁺ concentration of plasma increases and plasma Cl⁻ concentration decreases owing to sampling. During storage the plasma K⁺ concentration decreases far below resting levels in samples taken by cardiac puncture, whereas plasma Cl⁻ level returns to pre-stress levels. Owing to the sampling- and storage-induced changes in blood parameters, care must be taken to ensure that similar sampling procedure is employed throughout to allow reliable comparisons between groups to be made.     

Stress-induced testicular hyposensitivity to gonadotropin in rats. Role of the pituitary gland

The time course of stress-induced testicular hyposensitivity to gonadotropins was studied in hypophysectomized or naloxone-treated rats exposed to various periods of immobilization. Blood was collected from a chronically indwelling intra-atrial catheter every hour for luteinizing hormone (LH) and testosterone (T) measurement. Eight hours of immobilization completely suppressed T secretion without significant effect on LH. Human chorionic gonadotropin (hCG, 5 IU/rat, i.m.) induced a marked increase in plasma T levels in normal control groups 3 h post-injection while in immobilized rats the response was completely abolished, even after only 30 min of stress. In hypophysectomized rats, as expected, plasma T levels were undetectable, but, contrary to results obtained in normal animals, hCG induced a similar increase of plasma T levels both in control and stressed rats. Immobilization stress failed to inhibit plasma T values in hypophysectomized rats pretreated for 4 days with human menopausal gonadotropin (hMG) + hCG, while it did so in similarly treated normal animals. Naloxone induced a rise of plasma LH and T levels in control rats, but did not antagonize the stress-induced fall of plasma T concentration. In all groups, steroid testicular content mimicked variations of plasma T values. In particular, in stressed animals the lack of accumulation of testicular 17-hydroxyprogesterone probably reflected a normal activity of 17-20 lyase. These results indicate that stress induces very rapidly a state of Leydig cell hyposensitivity to gonadotropins and a blockade of T biosynthesis. The causal relationship between the two effects is presently not clear but these events seem to be due to stress-induced release of an inhibitory factor of pituitary origin other that endorphin.     

Ovarian steroidogenesis in Japanese patients with polycystic ovary syndrome

Gonadotropin and steroid hormone levels in both peripheral and ovarian venous blood were measured in samples obtained from 20 Japanese patients with polycystic ovary syndrome (PCOs) and 10 normal women in early follicular phase (normal women) by radioimmunoassay. The change in the amount of steroid hormone following intravenous human menopausal gonadotropin (HMG) or dexamethasone administration was investigated. The mean concentration in patients with PCOs was significantly higher than the concentrations found in normal women for LH (p less than 0.001), but not for FSH in peripheral blood. Significantly elevated ovarian venous steroid hormone levels in PCOs were found for 17 alpha-hydroxypregnenolone (p less than 0.05), progesterone (p less than 0.05), 17 alpha-hydroxyprogesterone (p less than 0.01), 4 delta-androstenedione (p less 0.01), testosterone (p less than 0.01), estrone (p less than 0.01) and estradiol (p less than 0.05), but not for dehydroepiandrosterone-sulfate (DHEAS). The ovarian dehydroepiandrosterone (DHEA) level was slightly elevated in PCOs. The concentration of ovarian 4 delta-androstenedione in PCOs reached twelve times as much as that in normal women. After the administration of HMG, all of the ovarian venus steroid hormone levels were elevated slightly and without significance in the short observation time for 10 min. The DHEAS level was suppressed while the ovarian DHEA level remained high in PCOs following dexamethasone administration. These findings seem to indicate there is no adrenal involvement and no adrenal-like component in the ovary of PCOs, and no evidence of 3 beta-hydroxysteroid dehydrogenase and/or aromatase deficiency in this study. The increase in the steroid hormone secretion in PCOs is explained by the increase in ovarian production in polycystic enlarged ovaries.     

Effect of 17-alpha-hydroxyprogesteronecapronate on sodium excretion and the renin-angiotensin-aldosterone-system in humans]

In seven healthy male subjects, a natriuretic effect of 17 alpha-hydroxyprogesterone caproate (17 alpha-OHPC) was demonstrated. Three of these subjects were kept on an uncontrolled diet and were examined over a period of 12 days. To the remaining four subjects, a single dose of 250 mg 17 alpha-OHPC was given intramuscularly after four days of intake of a chemically defined diet (Vivasorb). In this second test procedure, blood samples were taken in the recumbent position every two hours throughout a period of 12 h after the injection. For two more days and during the days before the administration of 17 alpha-OHPC, blood was taken at 8 a.m. before getting up from bed in same intervals, urine was collected for analysis of sodium and potassium excretion. During the first 12 h after the injection of 17 alpha-OHPC, the urinary sodium/potassium ratio significantly increased in all subjects. Plasma renin activity showed no characteristic changes at this time, whereas the plasma concentrations of aldosterone and cortisol decreased. The decrease of cortisol concentration started immediately after the injection and was more pronounced than that of plasma aldosterone. During the following 36 h, renin activity as well as aldosterone and cortisol concentrations in plasma showed an increase; in contrast, the sodium/potassium ratio decreased. On the basis of these results, the following effects of 17 alpha-OHPC are discussed: (1) an acute natriuresis which may be due to a competitive inhibition of aldosterone at the renal tubules, and (2) an inhibition of pituitary ACTH secretion or of adrenal steroid biosynthesis.     

皮质醇的周年变化与雌性虹鳟性腺成熟的关系

利用放射免疫分析法对饲养于恒定水温和自然光照下的雌性虹鳟血浆中皮质醇和性激素含量的周年变化进行了测定．结果表明：１）根据性腺结构指数和性激素分泌量判断,三龄时,雌性虹鳟达到性成熟;２）在血浆中不仅性激素而且皮质醇的变化水平与性腺结构指数的变化高度相关．排卵前性激素的水平都较高,伴随着排卵的进行性激素水平下降．而且在产卵季节虹鳟血浆中皮质醇水平也较高,三龄时皮质醇水平与性腺结构指数的相关系数为０．８６．这些结果提示,皮质醇在虹鳟的繁殖过程中可能发挥某种作用．     

Study of the hereditary differences in the cyclic nucleotide content of the blood serum in mice after exposure to stress and administration of phenazepam

Blood plasma content of cAMP and cGMP in C57BL/6, BALB/c mice and their reciprocal F1-hybrids has been studied at rest, upon exposure to stress induced in an open field technique and phenazepam injection at a dose of 0.05 and 0.1 mg/kg. Interstrain differences in baseline content and changes of nucleotide concentration in conditions of stress have been revealed. F1-hybrids inherit initial correlation between nucleotide content and the type of cAMP changes of C57BL/6 mice and cGMP changes of BALB/c mice. Phenazepam injection to C57BL/6 and BALB/c mice was shown to produce specific shifts in blood plasma cyclic nucleotide content.     

Influence of dietary fatty acids composition, level of dietary fat and feeding period on some parameters of androgen metabolism in male rats

The aim of the present study was to determine the effect of the composition of dietary fatty acids, the duration of feeding period and dietary fat level on androgen metabolism in male rats. One hundred and twelve Wistar rats were divided into 18 groups which were fed three diets containing different types of fat (rapeseed [R], palm [P] and fish [F] oil) at either normal fat level (w/w; 5%) or high fat level (20%) during one, three or six weeks. Blood plasma level of androgen (testosterone+dihydrotestosterone) and testicular activity of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) were investigated. In addition, androgen content in cytosol of the heart, the target organ, was measured. Androgen concentration in both blood plasma and heart cytosol extracts was measured by radioimmunoassay. The activity of 17Beta-HSD was expressed as a conversion of [3H]androstendione to [3H]testosterone in soluble fraction of gonadal homogenates. Plasma androgen concentration was influenced by a type of dietary fat (p<0.05). The highest plasma level of androgen was observed in animals fed R diets rich in unsaturated fatty acids. Significantly lower androgen concentration was demonstrated in rats fed P diets rich in saturated fatty acids. Only the feeding period factor significantly influenced androgen content in cytosol fraction of heart muscle cells (p<0.01). A positive correlation was found between plasma androgen concentration in plasma and cytosol fraction of the heart muscle cells (r=0.63, p<0.001). The feeding period (p<0.001) and dietary fat type (p<0.05) significantly affected the activity of 17beta-HSD. The least 17beta-HSD activity was observed in animals consuming the P-20% diet for six weeks. In summary, dietary fat type and feeding period, but not fat level, significantly affected both testosterone production and testosterone uptake by the target organ in male rats. It was found that a rapeseed diet rich in unsaturated fatty acids stimulated the testicular function in rats.     

Correlation between plasma steroid hormones and vitellogenin profiles and lunar periodicity in the female golden rabbitfish, Siganus guttatus (Bloch)

Characteristics of the lunar reproductive cycle in the golden rabbitfish, Siganus guttatus, were determined by histological observations of ovarian development, and immunological measurements of plasma steroid hormones, estradiol-17beta (E2), testosterone (T), 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP) and 17alpha,20beta,21-trihydroxy-4-pregnen-3-one (20beta-S), and vitellogenin (VTG). Ovarian and plasma samples were collected every week according to the lunar phases from May to July. Weekly change of gonadosomatic index (GSI) showed two peaks at the first lunar quarter in June and July. Yolky oocytes were also observed around this time. Histological observations revealed that the vitellogenic oocytes appeared again 1 week after spawning and developed synchronously. These results suggest that this species is a multiple spawner and the oocyte development is in a group-synchronous manner. Plasma steroid hormones (E2, T, DHP and 20beta-S) and VTG levels changed in parallel with changes in GSI. The peak of plasma VTG level occurred prior to spawning. These cyclic changes of plasma steroid hormones and VTG support the hypothesis that lunar periodicity is the major factor in stimulating reproductive activity of S. guttatus.     

Progestagen,androgen and oestrogen levels in plasma and ovarian follicular fluid during the oestrous cycle of the mare

The pattern of steroid hormone concentrations in the blood plasma of five mares was determined throughout eight oestrous cycles by radioimmunoassay. In three other mares the steroid hormone concentrations in the follicular fluid of 16 isolated follicles (⪖ 1 cm diameter) from both ovaries were analyzed on the first and third day of behavioural oestrus.The plasma levels of pregnenolone and progesterone as well as their 17α-hydroxylated metabolites showed similar ranges of concentration throughout the oestrous cycle. Luteolysis occurred 6 days prior to ovulation and was accompanied by a drop of all progestagens. Throughout the oestrous period (5 days prior to and including the day of ovulation) mean plasma concentrations of progestagens were <0.5 ng/ml and increased significantly one day after ovulation. Maximum plateau values were reached on day 6 after ovulation. A distinct (but not statistically significant) rise of androstenedione and testosterone plasma levels occurred during oestrus whereas dehydroepiandrosterone values increased significantly 6 days prior to ovulation and reached a maximum mean value of 1.14 ng/ml one day before ovulation. Levels then declined significantly on the day of ovulation. Oestrone and oestradiol-17β plasma concentrations increased significantly 4 and 3 days prior to the day of ovulation, respectively, and both remained elevated until one day before ovulation.A significant positive correlation could be detected between increasing follicle diameters and androstenedione as well as oestradiol-17β concentrations in the follicular fluid, whereas pregnenolone values showed a negative correlation with follicular diameter. Oestradiol-17β could be determined in 9 of the 16 follicular fluid samples. In 8 of these 9, oestradiol-17β predominated over all other steroid hormones.In view of the low concentrations of dehydroepiandrosterone detected in the follicular fluid, it is suggested that the increase in peripheral plasma values during oestrus is caused by an extra-follicular source(s).     

Testosterone stimulates myoglobin expression in different muscles of the mouse

The regulation of energy metabolism is one of the major functions of steroid hormones. This study was performed to explore whether testosterone can regulate the aerobic capacity of skeletal muscles via myoglobin expression. To study this, changes in testosterone level were quantified, and the level of myoglobin protein was analyzed using Western blot in mice subjected to 6 weeks of training (T) or testosterone administration (A). Both treatments significantly increased the plasma testosterone level when compared to the untrained (U) or control (C) group. Training induced a significant increase in the myoglobin content in gastrocnemius and plantaris muscles (287 and 83%, respectively). Testosterone administration increased myoglobin concentration in plantaris (183%) but not in gastrocnemius. In extensor digitorum longus muscle the protein content decreased slightly after exercise, but increased 78% after testosterone administration. In soleus and rectus femoris muscles the myoglobin content was unchanged after both treatments. The data show that testosterone and training have differential effects on the concentration of myoglobin in some, but not all muscles. This may have an influence on the aerobic capacity in mouse skeletal muscles. The data demonstrated that both testosterone administration and training induced an increase in plasma testosterone level. However, the effects of the treatments on the myoglobin concentration differ.     

Effect of etimizol on behavioral responses, brain serotonin concentration and plasma corticosteroid levels

The influence of ethymisol on behavioural reactions was studied on 100 albino rats in the "open field" and "passive avoidance" tests. It was shown that a 5 mg/kg dose of this neurotropic drug with synaptic effect, changes behavioural reactions, lowers the general emotional stress and emotional memory of the electro-cutaneous stimulation. Simultaneously the level of corticosteroids in the blood plasma significantly rises, while the serotonin content in the hypothalamus decreases. A direct correlation between the changes in the emotional stress and the content of corticosteroids in blood plasma is noted. The effects of ethymisol partially persists after adrenalectomy. Ethymisol in optimal doses may be used for regulation and lowering of emotional stress.