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Query: UMLS:C0848237 (acute stress)
 4,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Groups of female rats were injected daily for 14 days with 10 mg of cortisone acetate subcutaneously, to study the mechanisms of glucocorticoid suppression on the hypothalamic-pituitary-adrenal axis. Pituitary adrenocorticotropic hormone (ACTH) content, plasma ACTH, adrenal venous corticosterone, adrenal weights, and the catabolic effects on body weight were studied simultaneously (under stressful and non-stressful conditions) before, during, and up to six weeks after cortisone. This study confirmed the results of other investigators that cortisone acetate caused catabolic weight loss and adrenal atrophy, but it was noted to persist up to six weeks after the injections. Glucocorticoid acetate was more effective in causing ACTH-axis suppression than succinate or phosphate preparations, and the effects were dose and time related. Significant depletion of pituitary ACTH content, suppression of plasma ACTH, and corticosterone secretion occurred five to seven days after beginning cortisone acetate (p=<0.001); it was continuous throughout the injection schedule (p=<0.001); it remained for two to four weeks after the cortisone was discontinued (p=<0.001). The animals showed minimum plasma ACTH responsiveness to severe acute stress during this two to four-week suppression phase, but rapid recovery occurred thereafter. Plasma ACTH was undetectable up to six weeks post-cortisone when the animals were not under stress. This may be related to residual cortisone acetate found at the injection sites, or to an altered or different ACTH-axis control mechanism. The sequence of events during recovery from cortisone suppression appeared to be (1) repletion of corticotrophin-releasing hormone (by inference), (2) repletion of pituitary ACTH content, (3) secretion of plasma ACTH, (4) reversal of adrenal atrophy, and (5) subsequent secretion of corticosterone.
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PMID:Suppression of the hypothalamic-pituitary-adrenal axis after subcutaneous cortisone acetate administration in rats. 22 95

Neuroendocrine mechanisms are involved in modulation of the immune system, but the mode of action of the complex interplay between hormones and the immune system is only partially understood. This study examines the role of cortisol in monocyte differentiation and function, with regard to interleukin-1 beta (IL-1 beta) expression. The differentiation of the human histiocytic lymphoma cell line U 937 into macrophage-like cells by phorbol ester [phorbol myristate acetate (PMA)] is inhibited by cortisol. Some cells remain in suspension and continue to divide; others stop proliferation, but do not undergo full morphological differentiation. When cells are washed after 3 days to remove PMA and cortisol, all cells stop dividing and become fully differentiated. The PMA, therefore, commits the cells to differentiate even after its removal, while cortisol is only suppressive when present. Differentiated cells are shown to produce IL-1 beta mRNA when stimulated with lipopolysaccharide. This effect is inhibited by cortisol in a dose-dependent manner. After removal of cortisol, the least differentiated cells that remained in suspension were found to be overproducers of IL-1 beta mRNA after stimulation with lipopolysaccharide. This suggests that PMA induces a buildup of transcription-activating factors that were suppressed in the presence of cortisol. We conclude that the adrenal glucocorticoids that are elevated in acute stress conditions or major depression attenuate the differentiation and function of monocytes.
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PMID:Inhibition of macrophage differentiation and function by cortisol. 236 81

The present study was designed to compare the effect of leptin on acute colonic inflammation with that of acute stress exposure, which acts via the hypothalamic-pituitary-adrenal (HPA) axis. Sprague-Dawley rats of both sexes were administered intrarectally with acetic acid. Either leptin (10 microg/kg; i.p.) or saline was injected immediately before and 6 h after the induction of colitis. A group of rats was exposed to water avoidance stress (WAS) for 30 min at the 6th h of colitis induction. RU-486 (2 mg/kg; i.p.), a glucocorticoid receptor antagonist, was injected intraperitoneally, at 12 and 1 h before the initial leptin injection, and at 1 h before the second leptin injection or exposure to WAS. Rats were decapitated at 24 h and the distal 8 cm of the colon were removed for macroscopic and microscopic scoring, determination of tissue wet weight index (WI) and tissue myeloperoxidase activity (MPO). Acetic acid-induced colitis significantly increased macroscopic and microscopic damage scores, WI and MPO, compared to control group. Exposure to acute WAS or treatment with leptin reduced the elevations in damage scores, WI and MPO induced by colitis, but no additive inhibitory effect was observed when WAS and leptin were applied together. RU-486 treatment reversed the inhibitory effects of leptin or WAS on colonic inflammation. Our results demonstrate that exogenous leptin mimics the effects of HPA axis activation on colitis-induced inflammatory process. The results also suggest that the anti-inflammatory effect of leptin involves a tissue neutrophil-dependent mechanism and is dependent on the release of glucocorticoids.
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PMID:The anti-inflammatory effect of leptin on experimental colitis: involvement of endogenous glucocorticoids. 1500 61

In vivo effects of acute stress induced by corticosterone 21-acetate in male Gallus domesticus thymus are studied and the steroid actions are evaluated in terms of cell proliferation, apoptosis and cytokine response in 10- and 21-day-old chickens. Steroid treatment induced thymocyte apoptosis and cell death decreased in the cortical-medullar direction and was more evident in younger animals. 24 h after treatment, the observed effect was reversed. The mitotic activity and thymic cells containing cytokine-like molecules were also affected. Indeed, the acute stress stimulated cytokine immunoreactivity to anti-IL-1alpha, IL-6 and TNF-alpha antibodies both in epithelial cells and interdigitating cells located in medullar and cortical-medullar regions. The increased cytokine expression observed after 12 h was maintained after 24 h. The comparison between 10- and 21-day-old chickens showed a lower number of cells containing cytokine-like molecules in younger specimens. The present findings suggest that cytokines activated by acute stress in vivo could contribute to restoring immunological homeostasis and influence thymic glucocorticoid-mediated functions.
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PMID:Corticosterone 21-acetate in vivo induces acute stress in chicken thymus: cell proliferation, apoptosis and cytokine responses. 1516 29

The biochemical effects of acute and chronic psychological stress have been investigated in male Sprague-Dawley rats using a combination of 1H NMR spectral analysis of plasma and conventional hematological analyses. Animals were subjected to 35 consecutive days of 6-h sessions of stress, and following a 9 day break, were stressed for a further 6-h period. Plasma samples were collected at 0, 1, 3, and 6 h on days 1, 9, 21, 35, and 44, measured using 600 MHz 1H NMR spectroscopy, and analyzed by Principal Components Analysis. Time-dependent biochemical effects of psychological stress on a range of endogenous metabolites were evident and were correlated with the intensity of the stress response as defined by corticosterone and hematological parameters. Following acute stress, increases in the levels of glucose and ketone bodies, and decreases in the levels of acetate, alanine, isoleucine, lactate, leucine, valine, and lipoproteins, were observed. Chronic stress-induced increases in plasma levels of alanine, lactate (day 9), and leucine, valine, and choline (day 44) and decreases in acetate (day 9) and lipoprotein concentrations were observed. Positive correlations between plasma corticosterone level and glucose and glycerol, and between plasma lipoprotein concentrations and hemoglobin levels, were established using Projection to Latent Structures (PLS) analysis. This study indicates the potential of using NMR-based metabonomic strategies for the characterization of endogenous metabolic perturbations induced by psychological stressors and lifestyle choices.
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PMID:Metabonomic studies on the physiological effects of acute and chronic psychological stress in Sprague-Dawley rats. 1747 65

We investigated the effects of hydrocortisone acetate administered to pregnant rats over the last gestational week on some neuroendocrine characteristics in adult female and male offspring. Prenatal glucocorticoid eliminated sex dimorphism of the neurons nuclei volumes in the medial preoptic area and the suprachiasmatic nuclei. There was no elevation of blood plasma corticosterone level after noradrenaline infusion into the third brain ventricle in experimental males; meanwhile, in females adrenocortical response was augmented. Male offspring exhibited a decrease of plasma corticosterone response to an acute stress (1h restraint) that was not accompanied by post-stress changes neither in the hypothalamic noradrenaline content nor hippocampal glutamate decarboxylase activity. On the contrary, moderate augmentation of adrenocortical stress reactivity and inhibitory effect of GABAergic system were found in females. It was concluded that exposure to prenatal glucocorticoid is able to alter development of the neuroendocrine systems related to reproduction and stress responses both in males and females and resulted in modification of its sex-dimorphic features in adult life.
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PMID:Neuroendocrine disorders in adult rats treated prenatally with hydrocortisone acetate. 1869 98

Despite restrictions, exposure to lead (Pb) continues. Moreover, exposure varies and is often higher in lower socioeconomic status (SES) families and remains a significant risk to cognitive development. Stress is another risk factor. Lower SES may be a proxy for stress in humans. When stress and Pb co-occur, risk may be increased. A few previous experiments have combined Pb with intermittent or acute stress but not with chronic stress. To determine if chronic developmental stress affects outcome in combination with Pb, we tested such effects on growth, organ weight, brain monoamines, and response to an acute stressor. Sprague Dawley rats were gavaged with Pb acetate (1 or 10 mg/kg) or vehicle every other day from postnatal day (P)4-29 and reared in standard or barren cages. Subsets were analyzed at different ages (P11, 19, 29). Chronic stress did not alter blood Pb levels but altered HPA axis response during early development whereas Pb did not. Pb treatment and rearing each altered organ-to-body weight ratios, most notably of thymus weights. Both Pb and rearing resulted in age- and region-dependent changes in serotonin and norepinephrine levels and in dopamine and serotonin turnover. The model introduced here may be useful for investigating the interaction of Pb and chronic developmental stress.
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PMID:Effects of developmental stress and lead (Pb) on corticosterone after chronic and acute stress, brain monoamines, and blood Pb levels in rats. 2092 May 75

Fatty liver disease (FLD) is characterized by lipid accumulation in hepatocytes and is accompanied by secretory pathway dysfunction, resulting in induction of the unfolded protein response (UPR). Activating transcription factor 6 (ATF6), one of three main UPR sensors, functions to both promote FLD during acute stress and reduce FLD during chronic stress. There is little mechanistic understanding of how ATF6, or any other UPR factor, regulates hepatic lipid metabolism to cause disease. We addressed this using zebrafish genetics and biochemical analyses and demonstrate that Atf6 is necessary and sufficient for FLD. atf6 transcription is significantly upregulated in the liver of zebrafish with alcoholic FLD and morpholino-mediated atf6 depletion significantly reduced steatosis incidence caused by alcohol. Moreover, overexpression of active, nuclear Atf6 (nAtf6) in hepatocytes caused FLD in the absence of stress. mRNA-Seq and qPCR analyses of livers from five day old nAtf6 transgenic larvae revealed upregulation of genes promoting glyceroneogenesis and fatty acid elongation, including fatty acid synthase (fasn), and nAtf6 overexpression in both zebrafish larvae and human hepatoma cells increased the incorporation of 14C-acetate into lipids. Srebp transcription factors are key regulators of lipogenic enzymes, but reducing Srebp activation by scap morpholino injection neither prevented FLD in nAtf6 transgenics nor synergized with atf6 knockdown to reduce alcohol-induced FLD. In contrast, fasn morpholino injection reduced FLD in nAtf6 transgenic larvae and synergistically interacted with atf6 to reduce alcoholic FLD. Thus, our data demonstrate that Atf6 is required for alcoholic FLD and epistatically interacts with fasn to cause this disease, suggesting triglyceride biogenesis as the mechanism of UPR induced FLD.
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PMID:Activating transcription factor 6 is necessary and sufficient for alcoholic fatty liver disease in zebrafish. 2487 46

We applied an acute stress model to zebra fish in order to measure the changes in the metabolome due to biological stress. This was done by submitting the fish to fifteen minutes of acute confinement (netting) stress, and then five minutes for the open field and light/dark field tests. A polar extract of the zebra fish was then subjected to (1)H nuclear magnetic spectroscopy. Multivariate data analysis of the spectra showed a clear separation associated to a wide range of metabolites between zebra fish that were submitted to open field and light/dark field tests. Alanine, taurine, adenosine, creatine, lactate, and histidine were high in zebra fish to which the light/dark field test was applied, regardless of stress, while acetate and isoleucine/lipids appeared to be higher in zebra fish exposed to the open field test. These results show that any change in the environment, even for a small period of time, has a noticeable physiological impact. This research provides an insight of how different mechanisms are activated under different environments to maintain the homeostasis of the body. It should also contribute to establish zebra fish as a model for metabolomics studies.
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PMID:Effect of acute stresses on zebra fish (Danio rerio) metabolome measured by NMR-based metabolomics. 2509 33

An automated spectrophotometric method for total esterase activity (TEA) measurement in porcine saliva has been developed and validated, using 4-nitrophenyl acetate (4-NA) as substrate. The method was precise and accurate, with low limit of detection, and was able to measure samples with TEA activities up to 400IU/L without any dilution. In addition, the different enzymes contributing to TEA were characterized, being identified carbonic anhydrase VI (CA-VI), lipase, cholinesterase (ChE) and cholesterol esterase (CEL). TEA significantly increased (1.49-fold, P<0.01) in healthy pigs just after applying an acute stress stimulus consisting of nasal restraint, being lipase and cholinesterase the main responsible of this increase. TEA was significantly increased (1.83-fold, P<0.001) in a group of pigs with lameness; in this case, in addition to lipase and ChE, CA-VI also increased. The results found in this report indicate that TEA can be easily measured in porcine saliva with an accurate and highly reproducible automated method. Salivary TEA is mainly due to the activity of four enzymes: CA-VI, lipase, ChE and CEL, and these enzymes can change in a different way in situations of stress or disease.
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PMID:Total esterase measurement in saliva of pigs: Validation of an automated assay, characterization and changes in stress and disease conditions. 2844 10


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