Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0848237 (acute stress)
 4,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interrenal tissue from embryonic and larval rainbow trout (Oncorhynchus mykiss) was cultured in vitro and exposed to various doses of adrenocorticotropin (ACTH) to document the ontogeny of interrenal responsiveness to tropic stimulation. Resting and acute stress-induced changes in whole-body cortisol levels in vivo were also measured to determine if the corticosteroid stress response first develops with the onset of interrenal responsiveness to ACTH. No evidence was found that the hypothalamic-pituitary-interrenal (HPI) axis of rainbow trout is transiently activated prior to hatching. In vivo, a corticosteroid stress response was first observed 2 weeks after hatching, and stress-induced cortisol levels (at 1 hr poststress) were significantly higher 3 weeks after hatching than they were at 2 or 4 weeks after hatching. In contrast, cultured interrenal tissue produced significant levels of cortisol in response to ACTH at the time of hatching, and in vitro cortisol production by the interrenal increased significantly between 3 and 4 weeks after hatching. Interrenal sensitivity to ACTH did not change appreciably with development. We conclude that (1) the final maturation of the corticosteroid stress response in rainbow trout occurs at the level of the brain and/or sensory inputs and not at the level of the interrenal cell; (2) negative feedback mechanisms within the HPI axis develop 3 to 4 weeks after hatching; and (3) the period between 3 and 4 weeks after hatching may be homologous to the stress hyporesponsive period after birth in mammals and thus could be a stage when environmental influences can permanently alter the development of the corticosteroid stress response in rainbow trout.
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PMID:In vitro effects of ACTH on interrenal corticosteroidogenesis during early larval development in rainbow trout. 853 50

Double staining in situ hybridization studies have shown that angiotensin II (AII) type 1 receptors (AT1) in the hypothalamic paraventricular nucleus (PVN) are located primarily in corticotropin releasing hormone (CRH) neurons of the parvicellular subdivision. The purpose of these studies was to investigate the role of AII regulating the hypothalamic-pituitary adrenal (HPA) axis, by correlating AT1 receptor expression levels in the PVN with the known changes in activity of the HPA axis under different stress paradigms, and manipulation of circulating glucocorticoids. AT1 receptor mRNA was measured by in situ hybridization using 35S-labelled cRNA probes and AII binding by autoradiography using 125I[Sar1,Ile8]AII in slide mounted hypothalamic sections. AT1 receptor mRNA levels and AII binding in the PVN were reduced by about 20% 18 h after adrenalectomy remaining at these levels up to 6 days after. This effect was prevented by corticosterone administration in the drinking water, or dexamethasone injection (100 mg, s.c., daily). Conversely, dexamethasone injection in intact rats caused a 20% increase in AT1 receptor mRNA in the PVN. AT1 receptor mRNA and binding in the PVN increased 4 h after exposure to stress paradigms associated with activation of the HPA axis (immobilization for 1 h, or i.p. injection of 1.5 M NaCl), and remained elevated after repeated daily stress for 14 days. Unexpectedly, two osmotic stress models associated with inhibition of the HPA axis (60 h water deprivation or 12 days of 2% saline intake) also resulted in increased AT1 receptor mRNA levels and AII binding in the parvicellular PVN. In intact rats, the stimulatory effect of acute stress on AT1 receptor mRNA in the PVN was significantly enhanced by dexamethasone administration (100 micrograms, s.c., 14 h and 1 h prior to stress), while in adrenalectomized rats, with or without glucocorticoid replacement, stress reduced rather than increased, AT1 receptor mRNA. Dexamethasone, 100 micrograms, injected sc within 1 min the beginning of immobilization in adrenalectomized rats, increased AT1 receptor mRNA in the PVN to levels significantly higher than those after dexamethasone alone, indicating that the stress induced glucocorticoid surge is required for the stimulatory effect of stress on AT1 receptor mRNA. The data suggest that AT1 receptor expression in the PVN is under dual control during stress: stress-activated inhibitory pathways and the stimulatory effect of glucocorticoids. The lack of specificity of the changes in AT1 receptor expression in the PVN following stressors with opposite effects on ACTH secretion (osmotic and physical-psychological stress) does not support a role for AII as a major determinant of the response of the HPA axis during stress.
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PMID:Increased expression of type 1 angiotensin II receptors in the hypothalamic paraventricular nucleus following stress and glucocorticoid administration. 856 20

Though oxytocin and vasopressin are similar in structure and are produced in the same brain regions, they show specific responses under stress conditions. In humans, increases in peripheral blood vasopressin appear to be a consistent finding during many acute stress situations, while in rats, vasopressin secretion is unresponsive to several stimuli known to induce ACTH and catecholamine release. Even decreases in vasopressin levels during stress were described. In accordance with others, we observed enhanced vasopressin release in response to stress stimuli with an osmotic component such as hypertonic saline injection but also during exposure of rats to a warm environment. Immobilization stress which fails to induce vasopressin release was reported to increase hypothalamic vasopressin mRNA and plasma vasopressin levels in chronically adreno-demedullated rats. Unlike vasopressin, oxytocin may be considered a typical stress hormone responding to osmotic as well as other stress stimuli. We found that acute exposure of rats to immobilization stress resulted in an increase in oxytocin mRNA level. In addition, we have shown that magnocellular neurons of the paraventricular nucleus, but not the supraoptic nucleus, are essential for oxytocin release during immobilization stress. The release of posterior pituitary hormones represents an important component of the stress response.
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PMID:Vasopressin and oxytocin in stress. 859 99

The effects of acute stress on various indices of sympatho-adrenal, sympathoneural functions and hypothalamic-pituitary-adrenal (HPA) axis were examined both at central and peripheral sites in healthy, intact male Fischer 344/N rats of increasing age. Extracellular fluid (ECF) levels of norepinephrine (NE), its metabolites dihydroxyphenylglycol (DHPG), and methoxyhydroxyphenylglycol (MHPG), and of the dopamine metabolite dihydroxyphenylacetic acid (DOPAC), were measured 24 h after implantation of a microdialysis probe in the paraventricular nucleus (PVN) of the hypothalamus, and samples collected at 30-min. intervals during immobilization (IMMO). ECF levels of NE, DHPG, MHPG, and DOPAC were at baseline similar in both age groups, and all increased significantly in response to IMMO. The IMMO-induced increases in ECF levels of NE and MHPG were, however, significantly smaller in old than in young rats. Plasma levels of the dihydroxyphenylalanine (DOPA), -NE, epinephrine (EPI), DHPG, MHPG, dopamine (DA), DOPAC and HVA, were determined in different groups of young and old rats, cannulated in the tail artery, at baseline, and after 5, 30, 60, and 120 min of IMMO. Basal levels of DOPA, DHPG, MHPG, DA, DOPAC, HVA, NE and EPI were significantly higher in old than in young rats, and increased in plasma during IMMO. However, the magnitude of the increase in the majority of these compounds was significantly smaller in old than in young rats. Basal plasma levels of ACTH were similar among age groups, and basal plasma levels of corticosterone showed a significant aging-associated decline. Two i.v. doses (2 and 20 micrograms/kg BW) of rat CRF elicited significantly greater and delayed ACTH, and greater corticosterone responses in older rats, consistent with the pattern encountered in hypothalamic CRF deficiency. An i.v. injection of ACTH evoked lower corticosterone responses in the older (18 and 24 month old) than in the younger (2 and 8 month old) groups of rats, consistent with secondary adrenocortical atrophy in older animals. Steady-state mRNA levels of mineralocorticoid and glucocorticoid receptors were significantly decreased in the hippocampus of the 8-, 18-, and 24-month-old rats, compatible with maturational rather than senescent changes. CRF mRNA levels in the paraventricular nucleus of the hypothalamus, and levels of POMC mRNA in the anterior pituitary were significantly reduced with age. In conclusion, in this strain of rats, aging is associated with diminished responsiveness of central, and peripheral catecholaminergic systems to acute stress, and progressive hypothalamic CRH deficiency.
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PMID:Aging is associated in the 344/N Fischer rat with decreased stress responsivity of central and peripheral catecholaminergic systems and impairment of the hypothalamic-pituitary-adrenal axis. 859 25

In a previous study, we demonstrated that premenopausal women with visceral obesity have hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, characterized by an exaggerated hormone response to corticotropin-releasing factor (CRF) and corticotropin (ACTH) stimulation. The hypothalamic peptide flow that stimulates the pituitary, particularly after a physiological stress challenge, involves not only CRF, but also arginine-vasopressin (AVP), which synergizes the CRF capacity to stimulate pituitary hormone secretion. Previous studies in humans have demonstrated that combining AVP with CRF permits maximal stimulation of the pituitary, providing a more appropriate method of assessing pituitary hormone reserve. We therefore investigated the response of the HPA axis to combined CRF and AVP stimuli in obese women with different obesity phenotypes. Moreover, we examined hormonal and cardiovascular responses to several mental stress tasks, according to previously standardized procedures. Two groups of age-matched premenopausal eumenorrheic obese women with visceral (V-BFD) or subcutaneous (S-BFD) body fat distribution and a group of normal-weight healthy controls were investigated. All women randomly underwent the following protocol: (1) a combined CRF/AVP test (100 micrograms plus 0.3 IU intravenously [IV], respectively); (2) a standardized stress test, which consisted of completing two puzzles and a mental arithmetic test; and (3) a control saline test. Blood samples for ACTH and cortisol determinations were obtained before and during each test, and measurements of arterial blood pressure and pulse rate were made at regular intervals during the stress test. After combined CRF/AVP administration, ACTH and cortisol were significantly higher in V-BFD than in the other two groups. In contrast, no significant hormonal variation was found in either group during stress tasks. During the stress test, pulse rate (but not arterial blood pressure) significantly increased after 8 and 15 minutes in the V-BFD group, whereas no significant variation was found in S-BFD and control women. A significant correlation was present between the pulse rate and change in cortisol level during the stress test at minutes 8 (r=.54, P<.05) and 15 (r=.57, p<.01) in all women considered together. Subjective emotional involvement during stressful tasks was measured by a two-dimensional short verbal scale, which revealed that the stress section had a more significant impact in obese V-BFD than in S-BFD and control women. These data therefore confirm that women with visceral obesity have hyperactivity of the HPA axis, and that the combined CRF/AVP stimulation may offer a good tool for investigating pituitary reserve in this obesity phenotype. Moreover, the results indicate that these women probably have a hyperreactive sympathetic response to acute stress that seems interrelated to that of the HPA axis.
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PMID:Hypothalamic-pituitary-adrenal axis activity and its relationship to the autonomic nervous system in women with visceral and subcutaneous obesity: effects of the corticotropin-releasing factor/arginine-vasopressin test and of stress. 860 43

Hormones of the hypothalamic-pituitary-adrenal system were studied in 31 patients with early stage breast cancer and patients with metastatic breast cancer. Both groups received tamoxifen as first-line treatment. As a control group 15 age-matched healthy women participated in the study. The results showed that breast cancer patients had significant elevations in basal cortisol levels compared to controls. Metastatic breast cancer patients had higher cortisol levels than early stage breast cancer patients. No significant differences between breast cancer patients and controls were found in basal plasma ACTH and prolactin levels. These data provide evidence that breast cancer is associated with a hyperactive adrenal gland, which may be due to the physiological stress associated with the presence of (micro)metastases or tumor cells in the circulation, in combination with administration of tamoxifen. In response to a behavioral challenge increases were observed in plasma ACTH and prolactin. Metastatic breast cancer patients had a faster prolactin response to acute stress than healthy women. However, metastatic breast cancer patients showed a blunted ACTH response compared to healthy women. Stress-induced ACTH responses and basal cortisol levels were negatively correlated in the metastatic group only. Thus, the blunted ACTH response to the behavioral challenge might be related to hypercortisolemia suggesting that the pituitary corticotroph cell in metastatic cancer is appropriately restrained possibly by the negative feedback effects of chronic cortisol elevations. Interestingly, the behavioral challenge induced decreases in cortisol levels in all three groups. However, metastatic breast cancer patients had a faster cortisol decline compared to healthy women. We hypothesize that this is caused by increased metabolic clearance of cortisol due to increased utilization of metabolic substrates often observed in the presence of a tumor.
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PMID:Elevated basal cortisol levels and attenuated ACTH and cortisol responses to a behavioral challenge in women with metastatic breast cancer. 884 75

The tail-cast suspension rat model was developed to explore in ground laboratories the physiological effects of some of the stresses prevailing during space flight including and among them those of the headwards body fluid shifts. We recently showed in rats that an acute head-down tilt (45 degrees) from tail-cast orthostatic (OR) to antiorthostatic restraint (AOR) induced within 30 min and for 2 to 4 h an acute stress-like surge in plasma ACTH and corticosterone levels. Considering the proximity of the CRF producing neurons with the 3rd ventricle, we decided to explore the acute and longer-term effects of the OR/AOR tilt on the intra-cerebroventricular pressure (Picv) measured with an indwelling sensor-transmitter catheter stereotaxically implanted in the 3rd ventricle. At 1- or 10-min intervals the unit sent radiotelemetric signals for both Picv and motor activity (MA) to a receiver coupled with an automatic data analyser. The acute AOR-tilt induced within 10 min and for 60 min a 2.5-fold rise in Picv which receded to baseline between 60 and 90 min. During this time, the normally close correlation between Picv and MA was lost, as assessed by Spearman's rank coefficient. In a long-term experimental series we explored the evolution of both Picv and MA in individual rats subjected successively to a 7 day control phase (C). 7 days OR, and 3 days AOR. After the 1-h-long post-tilt rise of the Picv, the mean Picv levels measured for the next 3 days decreased significantly vs. both the preceding OR phase (-30%) and the initial C Phase (-40%). The circadian pattern of the diurnal Picv profile was impaired, as evidenced by a significant fall (i) in the night/day ratio (-25% vs. C). and (ii) even more in the spectral power of the circadian 1 c/24 h frequency (-85% vs. C). The simultaneously recorded MA fluctuations similarly displayed an altered diurnal pattern with a spectral power of the circadian frequency reduced to 7% of controls. However, contrary to the short-term experiment, in the long-term study the large alterations to both Picv and MA were strongly correlated, as during the control phase. The mechanisms involved in the swift post-tilt rise in the Picv together with an aroused corticotropic axis, and in the impact of sustained head-down restraint on CNS-controlled adaptive regulations including their circadian rhythms remain unknown.
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PMID:Effects of acute tilt from orthostatic to head-down antiorthostatic restraint and of sustained restraint on the intra-cerebroventricular pressure in rats. 893 Mar 21

We examined whether rats that were treadmill exercise trained (Tr) or chronically immobilized (CI) had similar responses by the hypothalamic-pituitary-adrenal (HPA) cortical axis to acute stress and whether the HPA responses interacted with the hypothalamic-pituitary-gonadal (HPG) axis. After 6 wk (1 h/day, 6 days/wk) of Tr or CI, plasma concentrations of adrenocorticotropic hormone ([ACTH]), [prolactin], and [corticosterone] were measured after familiar (treadmill running or immobilization) or novel (footshock) stress. Ovariectomized Sprague-Dawley females (n = 72) were implanted with capsules containing estradiol benzoate (E2) and randomly assigned in a 2-group (E2 vs. no E2) x 3 treatment (Tr vs. CI vs. sedentary) x 4 acute stressor [footshock vs. treadmill running (Run) vs. immobilization (Im) vs. no stress] x 3 recovery time (1 vs. 15 vs. 30 min) mixed-model analysis of variance. E2 capsules were removed from one-half of the animals 48 h before the first stressor session. After 10 min of acute stress, blood was drawn from a jugular catheter at 1, 15, and 30 min of recovery. [ACTH] and [prolactin] after footshock were higher in Tr rats with E2 compared with CI and sedentary rats without E2; recovery levels for sedentary animals were higher after Run compared with Im. The elevation in [corticosterone] from minute 1 to 15 of recovery was higher after the familiar Run and Im conditions. Our findings are consistent with an increased responsiveness of the HPA axis to novel footshock after treadmill exercise training that is additionally modulated by the HPG axis.
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PMID:Treadmill exercise training and estradiol increase plasma ACTH and prolactin after novel footshock. 896 59

A remote infusion and blood collection device (Dracpac) was used on free-ranging red deer stags to deliver i.v. a range of ACTH1-24 doses and collect blood for cortisol determination. In Experiment 1, conducted in September, saline and 1, 4, and 16 IU ACTH/100 kg bodyweight were infused (n = 5-7 per treatment). In Experiment 2 (November), 16 and 64 IU ACTH/100 kg were infused (n = 5 per treatment); and the response of animals to restraint was also assessed (n = 6). Pre-infusion concentrations of plasma cortisol were low (mean 6.5 +/- 1.0 ng/ml), and unaffected by infusion of saline. ACTH significantly elevated plasma cortisol concentrations, with mean peak concentrations occurring 20-40 min postinfusion. Duration of the response was dose dependent, ranging from 80-160 min. With increasing doses of ACTH, maximal peak heights plateaued at approximately 40 and 60 ng/ml in September and November, respectively; whereas the areas under the curves tended to increase. The minimum dose of ACTH that resulted in a maximal peak cortisol response was 4 IU. The maximum peak height of the cortisol response to 16 IU tended to be higher (P < 0.10) in November compared with September, suggesting that adrenal responsiveness may change over this period. The adrenal response to a 16-IU ACTH challenge in Experiment 2 resulted in similar plasma cortisol concentrations to an acute stress event (restraint). Four IU/100 kg ACTH i.v. is recommended as an appropriate dose for ACTH infusion studies in red deer stags. When used in conjunction with the Dracpac technique, it becomes a stress-free, repeatable procedure for assessing aspects of adrenal cortex physiology in free-ranging deer.
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PMID:Plasma cortisol responses to remote adrenocorticotropic hormone (ACTH) infusion in free-ranging red deer (Cervus elaphus). 898 70

We report on dynamic changes in plasma corticosteroid-binding globulin (CBG) binding and basal hypothalamic-pituitary-adrenal (HPA) activity following acute stress in adult rats. Plasma CBG binding was significantly reduced at 24 and 48 h following a single 60 min period of restraint. Basal levels of plasma ACTH and total corticosterone (B) during the light phase of the cycle were elevated at 24 h following restraint. These effects occurred only when animals were stressed in the light phase of the cycle; animals exposed to restraint stress during the dark phase of the cycle showed no change in plasma CBG binding or in basal HPA activity. Pituitary intracellular transcortin, which is derived from circulating CBG, was also decreased by restraint stress. The decrease in CBG binding was also associated with a significant increase in resting-state free B levels. Together, these effects produced a substantially (i.e. approximately 10-fold) increased 'basal' glucocorticoid signal 24 h following acute stress. These data suggest that the increase in the circulating glucocorticoid signal associated with acute stress endures well beyond the period of increased total B levels.
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PMID:Dynamic variations in plasma corticosteroid-binding globulin and basal HPA activity following acute stress in adult rats. 908 66


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