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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin-6 (IL-6) is produced by adrenal zona glomerulosa cells; its release is stimulated by several secretagogues, including IL-1 alpha, IL-1 beta, and angiotensin II. The present study reports that ACTH (0.1-100 nM) increased the release of IL-6 from primary cultures of rat adrenal cells in a concentration-dependent manner. This increase was accompanied by an increase in cAMP content in cell extracts and in the incubation medium. The dynamics of IL-6 release from the adrenal cells also were investigated using a perifusion system; approximately 50 min were required for the effects of IL-1 alpha, IL-1 beta, and ACTH on IL-6 release to become apparent. Following withdrawal of the secretagogues, IL-6 release returned to basal levels within 90-120 min. In some experiments, the adrenal zona glomerulosa was separated from the zona fasciculata/reticularis to determine the origin of secretagogue-stimulated IL-6 release. PGE2 and forskolin increased IL-6 release from both cell types, but maximal release from zona glomerulosa cells was more than 10-fold greater than that from zona fasciculata/reticularis cells. ACTH (0.1-100 nM) increased intracellular cAMP levels in cells from both cell types in a concentration-dependent manner, but increased IL-6 release only from zona glomerulosa cells. Dexamethasone, an inhibitor of IL-6 production in several tissues, had no effect on either basal or stimulated IL-6 production in the adrenal. Because IL-1 beta is produced primarily by tissues of the immune system, whereas ACTH is a classical endocrine hormone, we investigated the effect of interaction of these proteins on IL-6 release from the adrenal. Together, IL-1 beta and ACTH stimulation of IL-6 release was greater than the sum of the effects of each substance separately; however, IL-1 beta did not potentiate the effect of ACTH on cAMP levels. Similarly, IL-1 beta potentiated IL-6 release stimulated by forskolin and (Bu)2cAMP. Thus, the adrenal may be an important convergence point between the immune and endocrine systems, and because IL-6 release is regulated by IL-1 alpha, IL-1 beta, ACTH, and angiotensin II, and this cytokine stimulates corticosterone release, IL-6 may play an important paracrine role in integrating the signals derived from these systems.
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PMID:Adrenocorticotropin increases interleukin-6 release from rat adrenal zona glomerulosa cells. 131 Dec 32

The effects of hormones and cytokines on angiotensinogen production were studied in primary cultured rat hepatocytes. The basal secretion of angiotensinogen decreased during culture. The addition of dexamethasone and (Bu)2cAMP completely prevented this decrease. Angiotensinogen secretion by freshly plated hepatocytes was slightly increased in response to dexamethasone, but after 24 h in culture, hepatocytes no longer responded to dexamethasone alone. When hepatocytes were treated with (Bu)2cAMP, glucagon, or forskolin, angiotensinogen secretion increased in response to dexamethasone in a concentration-dependent manner. 17 beta-Estradiol and T3 failed to stimulate angiotensinogen secretion in either the presence or absence of (Bu)2cAMP. Interleukin-6 (IL-6) exhibited a stimulatory activity on angiotensinogen secretion, which was dependent on the presence of dexamethasone, whereas IL-1 and tumor necrosis factor had no effect in either the presence or absence of dexamethasone and/or (Bu)2cAMP. Unlike primary cultured hepatocytes, angiotensinogen secretion by rat hepatoma H4IIEC3 cells increased in response to dexamethasone alone. This increase was not enhanced by (Bu)2cAMP, but was enhanced by IL-6. Thus, in primary cultures of rat hepatocytes, neither glucocorticoid, cAMP, nor IL-6 alone stimulated angiotensinogen production, but a combination of glucocorticoid and cAMP or of glucocorticoid and IL-6 exhibited a stimulatory activity on angiotensinogen production. These results suggest that angiotensinogen production in the liver is synergistically regulated by these factors, whereas the hepatoma cell line H4IIEC3 lacks the regulatory mechanism of cAMP on glucocorticoid-induced angiotensinogen production.
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PMID:Stimulation of angiotensinogen production in primary cultures of rat hepatocytes by glucocorticoid, cyclic adenosine 3',5'-monophosphate, and interleukin-6. 131 Dec 38

Effects of Tumor Necrosis Factor (TNF), Interleukin-1 (IL-1), Interleukin-6 (IL-6) and Interferon-gamma (IFN-gamma) on the expression of Mn-superoxide dismutase (Mn-SOD) protein were investigated in human hepatoma cells, Hu-H1, which revealed resistance to the cytotoxicity of TNF and IL-1. Both TNF and IL-1 enhanced the Mn-SOD production to the level of 30- to 40-fold. IL-6 also increased the enzyme protein to 2- to 3-fold of the basal level without any cell proliferative effect. A specific antibody against IL-6 almost completely inhibited the induction of Mn-SOD. IL-6, as well as TNF and IL-1, appears to play some role in the Mn-SOD protein expression in human hepatoma cells.
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PMID:Induction of Mn-superoxide dismutase by tumor necrosis factor, interleukin-1 and interleukin-6 in human hepatoma cells. 131 66

Several hormones and cytokines stimulate the cellular Na+/H+ antiporter and this stimulation may be a signal transduction mechanism to mediate gene expression. We find that tumor necrosis factor rapidly stimulates both the Na+/H+ antiporter and the accumulation of mRNA coding for granulocyte-macrophage colony-stimulating factor and interleukin-6 in fibroblasts. Further experiments show that these phenomena occur independent of each other.
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PMID:Tumor necrosis factor stimulates Na+/H+ antiporter in human fibroblasts: dissociation between intracellular alkalinization and cytokine mRNA accumulation. 131 73

Two sublines of L929 cells with different interferon (IFN)-producing capacities synthesized IFN and interleukin-6 (IL-6) simultaneously in response to Sendai virus infection. IFN pretreatment primed the production of both cytokines. However, the difference in IL-6 production between the "high and low producer" L-cell sublines was about one magnitude of order larger than in the case of their IFN production. The determination of the corresponding mRNA levels also reflected this difference.
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PMID:Interferon pretreatment regulates interferon and interleukin-6 production in L929 cells in a coordinated manner. 131 62

The functional status of immune cells within human transplanted lungs was analyzed during cytomegalovirus (CMV) pneumonia complicating lung and heart-lung transplantations. The expression of interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) genes is a marker for the activation of macrophages as is that of serine esterase B (SE-B) gene for cytotoxic cells. The levels of expression of these genes by bronchoalveolar lavage (BAL) cells were determined by in situ hybridization. Eight cases of CMV pneumonia were included in this study. BAL cells from either rejection episodes (eight cases) or control transplanted patients experiencing neither infection nor allograft rejection (eight cases) were analyzed in parallel. In the control patients, virtually no cells expressed the IL-1 beta, the IL-6, or the SE-B genes. In contrast, these three genes were all expressed in samples from patients with CMV pneumonia. IL-1 beta gene-expressing cells were abundant in all infected patients (mean +/- SEM: 898 +/- 449 positive cells per 10(4) cells, p less than 0.001, compared with those in control patients). IL-6 gene-expressing cells were less numerous (92 +/- 74 positive cells per 10(4) cells) and present in five of the eight cases of CMV pneumonia. Activated cytotoxic cells were detected in seven of the eight cases of CMV pneumonia (36.5 +/- 19 SE-B gene-expressing cells per 10(4) cells, p less than 0.001). During allograft rejections (eight cases) IL-1 beta gene-expressing cells were present in all but one patient.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of macrophages and cytotoxic cells during cytomegalovirus pneumonia complicating lung transplantations. 131 30

In this study, we demonstrate that low but not high concentrations of interleukin-6 (IL-6) potentiate the cytotoxic effect of tumour necrosis factor-alpha (TNF-alpha) on U937 cells, in a dose-dependent manner. Killing of U937 cells by 100 U/ml of TNF-alpha, was maximally potentiated by 50 U/ml of IL-6. No potentiation of cell killing was observed when the concentration of IL-6 was increased to 4000 U/ml. At a concentration of 50 U/ml, IL-6 up-regulated TNF receptor expression but no change in TNF receptor number was observed when the concentration of IL-6 was increased to 4000 U/ml. Low concentrations of IL-6 can also induce sub-cytotoxic doses of TNF-alpha (0.1 and 0.33 U/ml) to kill U937 cells. Up-regulation of TNF receptors by IL-6 is dependent on de novo protein synthesis since receptor induction is abolished in the presence of cycloheximide. Taken together the data suggest that the potentiation of cell killing observed by a combination of these lymphokines is mediated in part by IL-6-induced changes in TNF receptor expression.
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PMID:Interleukin-6 regulates the cytotoxic effect of tumour necrosis factor on U937 cells. 131 49

Recent reports show that cytokines such as interleukin-1 (IL-1), tumor necrosis factor (TNF) and intravenously administered interleukin-6 (IL-6) stimulate adrenocorticotropic hormone (ACTH) release. Both IL-1 and TNF are known to be potent inducers of IL-6, a monokine produced by activated monocytes and folliculo-stellate cells of the pituitary gland and released from the hypothalamus. To determine the site(s) of action of IL-6 in the control of ACTH release, we injected human recombinant IL-6 into the third brain ventricle (3V) of freely moving, conscious male rats and measured ACTH by RIA. Both 0.05 pmole and 0.25 pmole doses of IL-6 were ineffective to change plasma ACTH in comparison to the values in controls. The maximal IL-6 dose tested of 1.25 pmole increased plasma ACTH within 15 min and the response lasted over 180 min. The effects of IL-6 on plasma ACTH were only partially paralleled by increased rectal temperature which suggests that hypothalamic temperature regulating centers were independent of these actions. To evaluate a possible direct effect on the pituitary, IL-6 was incubated in vitro with hemipituitaries under an atmosphere of 95% O2/5% CO2. After 1 hr of incubation IL-6 failed to cause any change in the secretion of ACTH throughout a concentration range of 10(-15) to 10(-9) M. Increased ACTH secretion into the incubation medium was found only with 10(-13) M IL-6 after a 2-hr incubation. The results support a possible role for IL-6 at both hypothalamic and/or pituitary levels to stimulate ACTH release.
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PMID:Induction of adrenocorticotropic hormone release by interleukin-6 in vivo and in vitro. 131 56

In order to determine the in vivo immune response in glioblastoma, monoclonal and polyclonal antibodies specific for inflammatory leukocytes and immunoregulatory products were utilized to stain tissue from four surgical specimens. The more activated the inflammatory cells, the more activated the tumors appeared to be. In the tumor with the largest infiltration (Case 3), inflammatory cells were stained for interferon-gamma, interleukin-2, interleukin-1 beta, lymphotoxin, tumor necrosis factor-alpha, and transforming growth factor-beta. The tumor cells also expressed interleukin-1 beta, interleukin-6, transforming growth factor-beta, tumor necrosis factor-alpha, and prostaglandin E. In contrast, in the tumor with the least inflammatory response (Case 1), the tumor cells did not express any cytokines. Expression of cytokines by glioma cells was modest in the two cases with modest inflammatory responses. Cellular inflammation, primarily consisting of T cells and macrophages with few or no B cells or natural killer cells, was two- to 15-fold greater outside the tumor than within. In contrast to leukocytes outside the tumor, which were activated and expressing class II major histocompatibility antigens, leukocytes within the tumor parenchyma or at the tumor's edge were negative for these antigens. In the four specimens studied here, the tumor cells themselves were also negative for class II major histocompatibility antigens. These findings, although preliminary, suggest that inflammatory cells within gliomas are inactivated and that glioma cells may increase the expression of immunosuppressive cytokines in response to an increased lymphocyte infiltrate. This observation, if corroborated by more extensive studies, may help to explain the failure of immune treatments in glioblastoma multiforme.
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PMID:Inflammatory leukocytes associated with increased immunosuppression by glioblastoma. 131 61

Interleukin-6 (IL-6) has actions on a variety of endocrine tissues. The cytokine is secreted by cells of the anterior pituitary and endocrine pancreas and has recently been shown to be produced by cultures of thyroid epithelial cells. In this study we have examined some of the factors which regulate IL-6 release from an immortalized human thyroid line (HTori3). IL-6 release over 24 h was stimulated by TSH (5000 microU/ml), by forskolin (0.01 mmol/l), by fetal calf serum (1-20%) and by epidermal growth factor (20 ng/ml). Stimulation was also apparent with gamma-interferon and with tumour necrosis factor at concentrations known to enhance class II major histocompatibility antigen expression by thyroid epithelium. The most potent factor tested was interleukin-1 (IL-1), which controls IL-6 release from other cell types. Threefold stimulation was found with 1 U/ml rising to 350-fold with 1000 U/ml. The effect of IL-1 took 2 h to develop and was blocked by cycloheximide (100 mumol/l). Stimulation was not markedly inhibited by pertussis toxin. Many of the actions of IL-1 are mediated by prostaglandin E2 (PGE2). At concentrations as low as 30 nmol/l, PGE2 stimulated IL-6 release but the maximum stimulation obtained with PGE2 was only threefold. The effect of IL-1 was not inhibited by indomethacin. These data provide further evidence that IL-6 is produced by human thyrocytes. The effect of IL-1 has not been demonstrated previously. Stimulation of IL-6 release by IL-1 did not appear to be mediated by prostaglandin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Release of interleukin-6 by human thyroid epithelial cells immortalized by simian virus 40 DNA transfection. 131 54


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