The secretion of glucocorticoids (GCs) is a classic endocrine response to stress. Despite that, it remains controversial as to what purpose GCs serve at such times. One view, stretching back to the time of Hans Selye, posits that GCs help mediate the ongoing or pending stress response, either via basal levels of GCs permitting other facets of the stress response to emerge efficaciously, and/or by stress levels of GCs actively stimulating the stress response. In contrast, a revisionist viewpoint posits that GCs suppress the stress response, preventing it from being pathologically overactivated. In this review, we consider recent findings regarding GC action and, based on them, generate criteria for determining whether a particular GC action permits, stimulates, or suppresses an ongoing stressresponse or, as an additional category, is preparative for a subsequent stressor. We apply these GC actions to the realms of cardiovascular function, fluid volume and hemorrhage, immunity and inflammation, metabolism, neurobiology, and reproductive physiology. We find that GC actions fall into markedly different categories, depending on the physiological endpoint in question, with evidence for mediating effects in some cases, and suppressive or preparative in others. We then attempt to assimilate these heterogeneous GC actions into a physiological whole. (Endocrine Reviews 21: 55‐ 89, 2000)

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How do glucocorticoids influence stress responses? Integrating permissive, suppressive, stimulatory, and preparative actions.

Over 60 years ago, Selye1 recognized the paradox that the physiologic systems activated by stress can not only protect and restore but also damage the body. What links these seemingly contradictory roles? How does stress influence the pathogenesis of disease, and what accounts for the variation in vulnerability to stress-related diseases among people with similar life experiences? How can stress-induced damage be quantified? These and many other questions still challenge investigators. This article reviews the long-term effect of the physiologic response to stress, which I refer to as allostatic load.2 Allostasis — the ability to achieve stability through change3 — . . .

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Protective and Damaging Effects of Stress Mediators

This meta-analysis reviews 208 laboratory studies of acute psychological stressors and tests a theoretical model delineating conditions capable of eliciting cortisol responses. Psychological stressors increased cortisol levels; however, effects varied widely across tasks. Consistent with the theoretical model, motivated performance tasks elicited cortisol responses if they were uncontrollable or characterized by social-evaluative threat (task performance could be negatively judged by others), when methodological factors and other stressor characteristics were controlled for. Tasks containing both uncontrollable and social-evaluative elements were associated with the largest cortisol and adrenocorticotropin hormone changes and the longest times to recovery. These findings are consistent with the animal literature on the physiological effects of uncontrollable social threat and contradict the belief that cortisol is responsive to all types of stressors.

http://anthro.vancouver.wsu.edu/media/Course_files/anth-260-edward-h-hagen/acute-stressors-and-cortisol-responses-a-theoretical-integration-and-synthesis-of-laboratory-research-1.pdf

Acute stressors and cortisol responses: a theoretical integration and synthesis of laboratory research.

Part I. From There to Here - Theoretical Background: 1. From visiousness to viciousness: theories of intergroup relations 2. Social dominance theory as a new synthesis Part II. Oppression and its Psycho-Ideological Elements: 3. The psychology of group dominance: social dominance orientation 4. Let's both agree that you're really stupid: the power of consensual ideology Part III. The Circle of Oppression - The Myriad Expressions of Institutional Discrimination: 5. You stay in your part of town and I'll stay in mine: discrimination in the housing and retail markets 6. They're just too lazy to work: discrimination in the labor market 7. They're just mentally and physically unfit: discrimination in education and health care 8. The more of 'them' in prison, the better: institutional terror, social control and the dynamics of the criminal justice system Part IV. Oppression as a Cooperative Game: 9. Social hierarchy and asymmetrical group behavior: social hierarchy and group difference in behavior 10. Sex and power: the intersecting political psychologies of patriarchy and empty-set hierarchy 11. Epilogue.

http://catdir.loc.gov/catdir/samples/cam032/98044356.pdf

Social Dominance: An Intergroup Theory of Social Hierarchy and Oppression

In response to stress, the brain activates several neuropeptide-secreting systems. This eventually leads to the release of adrenal corticosteroid hormones, which subsequently feed back on the brain and bind to two types of nuclear receptor that act as transcriptional regulators. By targeting many genes, corticosteroids function in a binary fashion, and serve as a master switch in the control of neuronal and network responses that underlie behavioural adaptation. In genetically predisposed individuals, an imbalance in this binary control mechanism can introduce a bias towards stress-related brain disease after adverse experiences. New candidate susceptibility genes that serve as markers for the prediction of vulnerable phenotypes are now being identified.

Stress and the brain: from adaptation to disease

Glucocorticoid binding was measured in resident and thioglycollate-elicited mouse peritoneal macrophages, rabbit alveolar macrophages, and human monocytes. Two assays of binding were used--an assay with intact cells in suspension or monolayers, and an assay of cytosol and nuclear forms of glucocorticoid receptors. The mononuclear phagocytes contained approximately equal to 4--10 X 10(3) high affinity receptor sites per cell, with dissociation constants of approximately equal to 2--8 nM dexamethasone. The binding to the saturable sites was specific for steroids with glucocorticoid or antiglucocorticoid activity. Cortisol, corticosterone, and progesterone competed with dexamethasone for binding, whereas estradiol, dihydrotestosterone, and 11-epicortisol competed very little. Binding of dexamethasone to cytosol and nuclear forms of the receptor complex and temperature-sensitive translocation of cytosol forms to nuclear forms were shown. At 37 degrees C the predominant form of the hormone-receptor complex was nuclear. These results demonstrate that corticosteroids interact with macrophages at physiological concentrations.

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Interaction of glucocorticoids with macrophages. Identification of glucocorticoid receptors in monocytes and macrophages.

Prostaglandin inhibition of T-cell proliferation is mediated at two levels.

The ups and downs of glucocorticoid physiology. Permissive and suppressive effects revisited.

GLUCOCORTICOIDS exert widespread suppressive effects on lymphocytes of most species1,2. Sensitivity to the hormones is thought to vary with the state of lymphocyte maturation and differentiation. Immature thymic lymphocytes, for example, are more sensitive than mature thymic-dependent lymphocytes1,3. Furthermore, in vitro studies have suggested that glucocorticoid sensitivity varies with the state of mitogen or antigen-induced activation. Nowell4 observed that prednisolone-21-phosphate reduced the number of mitoses induced in human peripheral blood lymphocytes by phytohaemagglutinin (PHA), and noted that this inhibition required the presence of glucocorticoids during the first 24 h of exposure to PHA. When glucocorticoids were added 48 h after PHA, a time when mitoses had not yet appeared, they had no effect on the number of mitoses measured 2 d later. Tormey et al.5 extended these results to show that prednisolone-21-phosphate inhibited incorporation of radiolabelled thymidine and cytidine into PHA-stimulated lymphocytes, and found that delayed addition of steroid resulted in diminished inhibition.

Glucocorticoid receptors and glucocorticoid sensitivity of mitogen stimulated and unstimulated human lymphocytes

Basal levels of glucocorticoids maintained by negative feedback regulation are known to modulate a wide range of physiological processes, through a variety of effects such as those on carbohydrate metabolism and “permissive” actions on effects of other hormones. Glucocorticoid levels increase sharply in response to the stress of any kind of threat to homeostasis. The increased levels have traditionally been ascribed the function of enhancing the organism’s resistance to stress. How known physiological and pharmacological effects of high levels of glucocorticoids might accomplish this function, however, has been a mystery.

Allan Munck

Papers

Interaction of glucocorticoids with macrophages. Identification of glucocorticoid receptors in monocytes and macrophages.

Prostaglandin inhibition of T-cell proliferation is mediated at two levels.

The ups and downs of glucocorticoid physiology. Permissive and suppressive effects revisited.

Glucocorticoid receptors and glucocorticoid sensitivity of mitogen stimulated and unstimulated human lymphocytes

Glucocorticoid physiology, pharmacology and stress