Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present study was designed to determine whether the glucocorticoid inhibitory feedback mechanism plays a role in the well-known tolerance of the neuroendocrine-immune axis response to repeated endotoxemia. Adult male rats underwent adrenalectomy (ADX) and were implanted with a subcutaneous corticosterone (compound B, CB, 75 mg) pellet, or sham operated and implanted with a placebo pellet. On the morning of day 8 after surgery (experimental day, D1), all rats received an intravenous injection of lipopolysaccharide (LPS) (25 microg/kg body weight) which was repeated daily until D5. Blood was drawn via intravenous indwelling catheters before (sample time zero) as well as 1, 2, 3 and 4 h after LPS treatment on D1, 3 and 5 for measurements of corticotropin (ACTH), CB, tumor necrosis factor-alpha (TNF-alpha) and leptin. In sham animals, tolerance to repeated LPS administration was complete by D5 for the corticotrope axis and the immune response. In addition, LPS was found to stimulate leptin secretion on day 1 in intact rats, an effect that also disappeared thereafter. ADX + CB rats showed only a partial tolerance of the corticotrope axis on D5, whereas tolerance of the immune response was similar to that found in sham animals. Interestingly, the acute stimulation of leptin secretion by LPS in ADX + CB rats was qualitatively similar to that of intact controls on D1, but plasma leptin levels were significantly reduced on D3 and 5 compared to controls. Our results demonstrate that the adrenal response tolerance of the hypothalamo-pituitary-adrenal axis to repeated endotoxemia. In addition, our finding that TNF-alpha secretion follows the same pattern in sham-operated and in adrenalectomized animals suggests that unlike the corticotrope axis, tolerance of the immune response does not depend upon stimulated CB levels. The decrease in circulating levels of leptin following ADX is consistent with the stimulatory effects of glucocorticoids on leptin secretion. However, our finding of an acute stimulation of leptin secretion by LPS in ADX + CB animals demonstrates that this effect of endotoxemia is at least partially glucocorticoid independent.
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PMID:Role of glucocorticoids in the response of the hypothalamo-corticotrope, immune and adipose systems to repeated endotoxin administration. 1034 77

The cytokine and neuroendocrine host responses to experimental challenge with lipopolysaccharide (LPS) were studied in human immunodeficiency virus (HIV)-infected subjects and uninfected control subjects. Elevations in circulating concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8 were significantly greater in HIV-infected subjects than control subjects after LPS challenge. All subjects showed a significant increase in circulating concentrations of adrenocorticotropin, cortisol, and norepinephrine after LPS challenge, but there was not a significant difference between the responses of these hormones in the HIV-infected and -uninfected subjects. Compared with the control subjects, the HIV-infected subjects had a significantly reduced IL-10 response and a reduced IL-1 receptor antagonist response. It is concluded that the TNF-alpha, IL-6, IL-8, and IL-10 cytokine responses to LPS in vivo are disrupted in HIV subjects but that this is not related to disruption of the hypothalamo-pituitary-adrenal axis.
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PMID:In vivo cytokine and neuroendocrine responses to endotoxin in human immunodeficiency virus-infected subjects. 1035 68

The neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) modulates production of proinflammatory cytokines in brain tissue and in peripheral inflammatory cells. Transcription of the genes for these proinflammatory cytokines is regulated by the nuclear factor kappaB (NF-kappaB). NF-kappaB is also activated by proinflammatory cytokines. Degradation of the cytoplasmic inhibitor IkappaBalpha protein results in activation of NF-kappaB. Because of increasing evidence that NF-kappaB is involved in brain injury and inflammation and neurodegenerative disease, we examined whether alpha-MSH inhibits activation of NF-kappaB and limits degradation of IkappaBalpha protein induced by lipopolysaccharide (LPS) in human glioma cells (A-172) and in mouse brain. Electrophoretic mobility shift assays of nuclear extracts from A-172 cells and whole mouse brains stimulated with LPS revealed that alpha-MSH does suppress NF-kappaB activation. Western blot analysis demonstrated that alpha-MSH preserved expression of IkappaBalpha protein in vitro (glioma cells) and in vivo (brain tissue). Chloramphenicol acetyltransferase assay indicated that alpha-MSH suppresses NF-kappaB-dependent reporter gene expression induced by LPS in A-172 cells. The findings are consistent with the possibility that the anti-inflammatory action of alpha-MSH in CNS inflammation occurs via modulation of NF-kappaB activation by peptide-induced inhibition of degradation of IkappaBalpha protein.
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PMID:alpha-melanocyte-stimulating hormone inhibits NF-kappaB activation and IkappaBalpha degradation in human glioma cells and in experimental brain inflammation. 1036 47

The role of endogenous interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in modulating the hypothalamic-pituitary-adrenal (HPA) axis response was examined in male C57BL/6 mice injected with endotoxin (lipopolysaccharide, LPS) or saline at 24-hour intervals for 4 or 8 consecutive days. The mice were divided into four groups: (1) LPS injections for 4 or 8 days and LPS injection on day 5 or 9, respectively (LPS-LPS); (2) LPS injections for 4 or 8 days and saline injection on day 5 or 9, respectively (LPS-saline); (3) saline injections for 4 or 8 days and LPS injection on day 5 or 9, respectively (saline-LPS), and (4) saline injections for 4 or 8 days and saline injection on day 5 or 9 (saline-saline). The mice were sacrificed by decapitation 2 h after the last injection and plasma levels of hormones and cytokines and tissue levels of IL-1beta were measured. Plasma adrenocorticotropin (ACTH) levels were significantly attenuated in the LPS-LPS group compared with the dramatic increases in the saline-LPS group following 4 or 8 days of endotoxin treatment. Plasma corticosterone concentrations were comparable in the LPS-LPS group after 4 days' treatment, but significantly lower following 8 days of treatment when compared with saline-LPS group. Repeated endotoxin treatment followed by a single saline injection (LPS-saline) did not alter the levels of IL-1beta in plasma or any of the tissues examined. IL-1beta levels in the hippocampus, hypothalamus, adrenal gland and plasma were elevated to comparable levels in the saline-LPS and LPS-LPS groups after 4 days of treatment. In contrast to the plasma IL-1beta response, TNFalpha levels were dramatically increased in the saline-LPS group but not in the LPS-LPS group following the 4-day treatment regimen. Increases in IL-1beta concentrations were seen in all tissues following one endotoxin challenge in the saline-LPS group following the 8-day treatment regimen, while increases were significantly attenuated in the hypothalamus, adrenal gland and plasma in LPS-LPS for 8 days. The sustained increases in tissue levels of IL-1beta following 4-day endotoxin treatment appears to have functional consequences since [125I]IL-1alpha binding was significantly decreased in the LPS-saline group compared with the saline-saline group. Furthermore, [125I]IL-1alpha binding was markedly reduced in the LPS-LPS group compared with the saline-LPS group. There was a significant positive correlation between plasma ACTH and IL-1beta after a single and repeated LPS treatment for 4 days, while a significant correlation was seen between plasma ACTH and TNFalpha following one but not repeated LPS treatment. These data demonstrate a differential regulation of IL-1beta and TNFalpha by repeated endotoxin treatment and suggest that while TNFalpha may be important modulating the attenuated pituitary adrenocortical response following the 4-day endotoxin treatment, IL-1beta appears to be the primary regulator of the response following the 8-day endotoxin treatment in the regulation of the HPA axis.
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PMID:Differential effects of one and repeated endotoxin treatment on pituitary- adrenocortical hormones in the mouse: role of interleukin-1 and tumor necrosis factor-alpha. 1039 14

The neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) and its C-terminal tripeptide alpha-MSH11-13 modulate production of proinflammatory cytokines and inhibit inflammation. We examined whether systemic alpha-MSH and alpha-MSH11-13 inhibit activation of the nuclear transcription factor, nuclear factor kappa B (NF-kappaB), a factor that is essential to expression of proinflammatory cytokines, in experimental murine brain inflammation induced by lipopolysaccharide. Electrophoretic mobility shift assays of nuclear extracts demonstrated that parenteral alpha-MSH inhibited NF-kappaB activation. Western blot analysis revealed that this inhibition was linked to alpha-MSH-induced preservation of expression of IkappaBalpha protein in the brain. The effects of alpha-MSH on NF-kappaB and IkappaBalpha were paralleled by pretreatment with alpha-MSH11-13. Similar effects of the two peptides were observed in mice with nonfunctional melanocortin 1 receptors (MC1R), ruling out the possibility that this receptor subtype is essential to the influence on NF-kappaB. These findings indicate that alpha-MSH peptides given systemically can inhibit NF-kappaB activation induced in acute brain inflammation even in the absence of MC1R.
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PMID:Systemically administered alpha-melanocyte-stimulating peptides inhibit NF-kappaB activation in experimental brain inflammation. 1041 2

The corticotropin-releasing hormone neurons of the hypothalamic paraventricular nucleus are the final common pathway of the neuroendocrine adaptative response to a variety of stressors. To meet varied homeostatic needs, corticotropin-releasing hormone neurons exhibit a marked phenotypical plasticity, enabling them to rapidly modify their neuroendocrine output. In particular, they synthesize the neuropeptides vasopressin and neurotensin. Under many experimental circumstances, it is observed that corticotropin-releasing hormone and vasopressin are regulated in parallel, whereas the expression of neurotensin seems dissociated, in these neurons, evoking different transcriptional control over the co-existing neuropeptides depending on the adaptative response required. Using radioactive and dual-label in situ hybridization techniques, we have studied the respective expression of paraventricular corticotropin-releasing hormone, vasopressin and neurotensin messenger RNAs in the context of an immune challenge. A single intraperitoneal injection of the endotoxin lipopolysaccharide was administered to adult male rats that were killed 8 h later. Compared to control animals, lipopolysaccharide-injected rats showed elevated plasma corticosterone (614+/-65 vs 185+/-40 ng/ml in control) and increased expression of paraventricular corticotropin-releasing hormone messenger RNA (+200%); expression of neurotensin messenger RNA was induced in about one-third of corticotropin-releasing hormone neurons, whereas vasopressin messenger RNA expression remained unchanged. Therefore, in this experimental context and at the time-point examined, co-existing corticotropin-releasing hormone and vasopressin appeared differentially expressed, and an additional stimulus (inflammation) is demonstrated to result in neurotensin expression in neuroendocrine corticotropin-releasing hormone neurons. Neurotensin may be released in the pituitary portal blood to trigger pituitary response associated with mobilization of the immune system.
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PMID:Immune challenge-stimulated hypophysiotropic corticotropin-releasing hormone messenger RNA expression is associated with an induction of neurotensin messenger RNAs without alteration of vasopressin messenger RNAs. 1043 May 2

We have previously described the regulation of interleukin-1 receptor antagonist (IL-1ra) protein secretion and expression by IL-1, glucocorticoids and corticotropin-releasing hormone in monocytes in culture. In the present work, we analyze the direct effect of adrenocorticotropic hormone (ACTH) and beta-endorphin on the expression and secretion of IL-1ra by human monocytes in culture. ACTH exerted a dose-dependent inhibitory effect on lipopolysaccharide (LPS)-induced IL-1ra production and mRNA expression. Basal IL-1ra levels were not affected by treatment with any ACTH dose. In contrast, on human monocytes, beta-endorphin at concentrations as low as 10 pg/ml produced an increase of basal IL-1ra protein secretion and mRNA expression, this effect being reverted by pretreatment with naloxone. No effect of beta-endorphin was observed either in IL-1ra mRNA expression or protein secretion when cells were treated with LPS. The different effects of ACTH and beta-endorphin could account for their differential contribution to the inflammatory response: while ACTH contributes to the glucocorticoid overall control of the inflammatory response, beta-endorphin exerts an inhibitory tone on the resting IL-1 system. Because IL-1ra is essential in setting the level of monocyte and inflammatory response its differential regulation by the HPA axis hormones contributes to regulating the IL-1/inflammatory temporal response.
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PMID:Differential regulation of interleukin-1 receptor antagonist by proopiomelanocortin peptides adrenocorticotropic hormone and beta-endorphin. 1047 56

The A1 and A2 brainstem noradrenergic cell groups project to the hypothalamic paraventricular nucleus (PVN), which is involved in integrating the stress response. Bi-directional communication between the brain and immune system is well established, with both neuroendocrine and immune responses being activated by lipopolysaccharide (LPS). The mechanisms underlying such activation and differences between alternative routes of administration remain unclear. We examined activation of the PVN and A1/A2 cell groups, by assessing c-fos mRNA, or counting Fos-positive neurons in either the PVN or in brainstem A1/A2 cell groups 3 h after intracerebroventricular (i.c.v.) LPS, in control and adrenalectomized (ADX) rats. We also measured corticotropin-releasing hormone (CRH) mRNA in the PVN, and plasma corticosterone (CORT) levels. A group of ADX/CORT-replaced animals received i.c.v. LPS, and CRH mRNA and Fos peptide in the PVN were analysed. ADX increased CRH mRNA in the PVN, as did LPS, but no enhancement of this response was seen in LPS/ADX animals. C-fos mRNA also increased in both the PVN and the A2 cell group following LPS, but this response was potentiated by ADX. Fos peptide-containing cells increased in the PVN and A2 following LPS, and this change was amplified by ADX. Only 11.25% of Fos was found in DBH-positive (putative noradrenergic) neurons, suggesting activation of neurons containing other transmitters. ADX/LPS/CORT animals showed numbers of Fos neurons in the brainstem, and CRH mRNA levels in the PVN which were comparable to intact/LPS animals. Central LPS activates the hypothalamo-pituitary-adrenal axis, a process mediated partly by brainstem noradrenergic neurons, suggesting the involvement of afferent/efferent pathways within the brain. Peripheral administration of LPS involves activation of vagal inputs leading to the nucleus tractus solitarius. We suggest that centrally administered LPS activates the A2 cell group by a mechanism independent of the vagus. In the absence of CORT, despite the lack of a CRH mRNA response, an exaggerated c-fos and peptide response to LPS is observed, which is reversed following CORT pretreatment.
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PMID:Central LPS-induced c-fos expression in the PVN and the A1/A2 brainstem noradrenergic cell groups is altered by adrenalectomy. 1051 80

The purpose of this work was to compare the plasma adrenocorticotropin (ACTH), corticosterone and interleukin-6 (IL-6) responses that rats of the outbred Sprague-Dawley strain obtained from two different vendors: Charles River (CR) and Harlan (HSD). Basal plasma ACTH and IL-6 concentrations were similar in rats from either vendor (HSD or CR), while CR animals exhibited slightly elevated corticosterone levels in late afternoon. Inflammatory stimuli such as lipopolysaccharide (LPS) (1 microgram/kg, i.v.) or turpentine (50 microliter/100 g, i.m.) which induce the production of endogenous cytokines, produced a significantly larger ACTH response in CR, compared to HSD rats, while the overall corticosterone responses were comparable in both rat groups. This could probably not be accounted for by a greater ACTH responsiveness in CR rats per se because CR and HSD rats showed similar peak ACTH responses to electrofootshock. Furthermore, in contrast to when the stimulus was one that induced endogenous cytokine production, the administration of exogenous interleukin-1beta (IL-1beta, 200 ng/kg, i.v.) produced a 2-fold greater rise in plasma ACTH concentrations in HSD rats compared to CR rats. The plasma IL-6 responses to the inflammatory stimuli showed a similar pattern to ACTH, with LPS and turpentine tending to pruduce greater IL-6 responses in CR rats, though these differences were not statistically significant. In contrast HSD rats had a significantly greater IL-6 response to IL-1beta than did CR rats. Collectively, these results show that Sprague-Dawley rats obtained from different commercial sources can differ in immune-neuroendocrine responses to inflammatory stimuli.
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PMID:Sprague-Dawley rats obtained from different vendors exhibit distinct adrenocorticotropin responses to inflammatory stimuli. 1051 81

Pregnancy and lactation are times of prolonged physiological changes affecting the neuroendocrine and immunological systems. One well-characterized change is the neuroendocrine hyporesponsiveness to acute stressful stimuli. We have now designed studies to see whether there is an alteration in the response of the hypothalamic-pituitary-adrenal (HPA) axis to an immunological inflammatory challenge and to ascertain whether lactating animals show altered neural and endocrine responses to inflammatory stimuli. Lactating (day 9-12 postpartum) or virgin control Sprague-Dawley female rats were injected with either 200 microg of endotoxin (lipopolysaccharide, LPS ) or sterile saline given i.p. Trunk blood or jugular blood was collected from the animals at 2 h or hourly over 6 h after injection. Both plasma adrenocorticotropic hormone (ACTH) and corticosterone concentrations were significantly higher in saline treated lactating animals compared with the virgin group. LPS significantly elevated circulating levels of plasma ACTH and corticosterone in both virgin and lactating animals compared with saline controls, however, hormone responses to LPS were significantly reduced in lactating animals relative to virgin controls. Corticosterone-binding globulin concentrations were lower in lactating animals compared to virgin animals and LPS decreased concentrations in virgin, but not lactating rats. Analysis of cfos mRNA in the paraventricular nucleus (PVN) of the hypothalamus revealed that 2 h following injection there was a increase in cfos expression only in the virgin animals treated with LPS, compared to all other treatment conditions. Corticotropin-releasing hormone (CRH) mRNA expression was overall greater in virgin animals, but was increased to similar extent in both virgin and lactating animals treated with LPS. Primary arginine vasopressin (AVP) mRNA transcripts were increased 2 h following LPS injection, but a greater increase in expression was seen in virgin animals. These data demonstrate that there is a lower level of free circulating glucocorticoid in response to inflammatory stimuli and suggests that communication between the immune and endocrine systems may be altered during lactation.
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PMID:The hypothalamic-pituitary-adrenal axis response to endotoxin is attenuated during lactation. 1052 Jan 36


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