Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fetal rat hepatocytes incubated in the absence of hormonal signals, or under proliferative (presence of epidermal growth factor [EGF]) or differentiative (presence of dexamethasone) culture conditions, showed responsiveness to interleukin-6 (IL-6). Northern blotting analysis for some typical acute phase genes such as haptoglobin and other proteins not previously identified as acute-phase reactants, such as alpha-fetoprotein, beta 2-microglobulin, and fibronectin, showed a positive modulation by IL-6, in a dose-dependent manner. However, a well-characterized negative acute-phase reactant such as albumin was not responsive to IL-6. The well-established synergism between glucocorticoids and IL-6 on inducing transcription is absent in fetal hepatocytes. Conversely, the combination of IL-6 and EGF produced different patterns of expression, depending on the messenger RNA (mRNA) analyzed. Thus, EGF abolished the increased mRNA levels of haptoglobin caused by IL-6 but had no effect on other genes such as alpha-fetoprotein and fibronectin.
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PMID:Regulation of gene expression by interleukin-6 in fetal rat hepatocyte primary cultures: role of epidermal growth factor and dexamethasone. 748 87

Angiotensinogen has been assumed to be an acute-phase protein, because some forms of acute inflammation, eg, the injection of lipopolysaccharide or cellite or partial hepatectomy, increased the hepatic synthesis of angiotensinogen. In addition, the well-characterized nephrectomy-induced stimulation of angiotensinogen was thought to represent an acute-phase reaction. To evaluate this hypothesis, we examined changes in angiotensinogen secretion by the isolated perfused rat liver after the systemic administration of turpentine or lipopolysaccharide as well as in response to nephrectomy or sham nephrectomy. Comparison was made with the secretion of two typical acute-phase proteins, alpha 1-acid glycoprotein and alpha 2-macroglobulin, and with the secretion of the negative acute-phase protein albumin. All forms of experimental surgery stimulated the secretion of both control acute-phase proteins several-fold. In contrast, the response of angiotensinogen was not uniform; lipopolysaccharide and bilateral nephrectomy stimulated secretion twofold to threefold, sham nephrectomy had no effect, and turpentine decreased the secretion to 30% of the control level. A similar inhomogeneity was found in an additional experiment performed to analyze the direct effects of interleukin-1 or interleukin-6 on the secretion of angiotensinogen by freshly isolated hepatocytes. Interleukin-6 increased but interleukin-1 decreased the mRNA and secretion of angiotensinogen, whereas both cytokines increased the secretion of both acute-phase proteins. Because of this nonuniform behavior of angiotensinogen, it is premature to classify angiotensinogen as an acute-phase protein until a specific function for angiotensinogen during acute inflammation is known.
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PMID:Angiotensinogen: an acute-phase protein? 750 96

To clarify the mechanism involved in regulating the secretion of albumin and alpha 1-acid glycoprotein by rat hepatocytes, we studied hepatocyte culture and cocultures of hepatocyte and liver nonparenchymal cells. The secretion of alpha 1-acid glycoprotein by hepatocytes was stimulated and that of albumin was inhibited by combinations of dexamethasone and monokines, especially by dexamethasone and interleukin-6. The secretion of these proteins was equally inhibited during stimulation by lipopolysaccharide in cocultures. The inhibitory effect of sinusoidal endothelial cells was smaller than that of Kupffer cells. This inhibition was partially abolished by blocking the nitric oxide synthase pathway in cocultured cells and was completely abolished by dexamethasone. In conclusion, the secretion of albumin and alpha 1-acid glycoprotein by hepatocytes was regulated by monokines, dexamethasone, and the inducible nitric oxide synthase pathway in hepatocytes and liver nonparenchymal cells in vitro.
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PMID:Regulation of hepatocyte albumin and alpha 1-acid glycoprotein secretion by monokines, dexamethasone, and nitric oxide synthase pathway: significance of activated liver nonparenchymal cells. 751 18

Interleukin-6 (IL-6) has been ascribed significant roles in both hematopoiesis and the immune response, although its contribution to host defence as a whole is poorly understood. Because short-term IL-6 treatment was previously shown to stimulate megakaryocytopoiesis, we investigated the effect of long-term administration of IL-6 on megakaryocytopoiesis and other systemic parameters in nonhuman primates. We chose a small primate, the marmoset (Callithrix jacchus), which enabled long-term administration at high doses. Recombinant human IL-6 (rhIL-6) administered at doses of up to 1,000 micrograms/kg/d over 4 and 9 weeks caused a sustained twofold to threefold increase of thrombocyte counts, peaking at 4 weeks. Thrombocyte counts declined thereafter, despite continuing IL-6 administration. The number of bone marrow megakaryocytes at 4 and 9 weeks was not increased compared with controls, but the ploidy grade was augmented, suggesting that IL-6 effects are restricted to mature megakaryocytes in vivo. An acute-phase protein response was observed within 24 hours after the first IL-6 administration and reached a maximum after 1 week of IL-6 administration at 25 micrograms/kg. Serum C-reactive protein, haptoglobin, and ceruloplasmin were increased, whereas albumin and transferrin levels declined. The acute-phase protein response was not associated with any morphologic evidence of hepatocellular damage. The increased levels of Ig and soluble IL-2 receptor in the serum levels reflected systemic immunostimulation. There was no evidence of renal mesangioproliferative pathology. Antibodies against rhIL-6 developed within 2 weeks, continuously increasing during the course of the study. High titers of neutralizing antibodies appeared concomitantly with the decrease in platelet counts and decline in acute-phase proteins. Therefore, despite the pleiotropic effects of IL-6 observed in vitro, long-term administration of IL-6 caused a selective and sustained stimulation of thrombopoiesis in marmosets that was only ablated by the appearance of neutralizing antibodies, and high doses were well tolerated in marmosets. A long-term targeting of IL-6 to cells of the megakaryocytic lineage, without evoking general toxicity, confirms the potential therapeutic usefulness of rhIL-6 for the chronic treatment of thrombocytopenic patients.
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PMID:Long-term interleukin-6 administration stimulates sustained thrombopoiesis and acute-phase protein synthesis in a small primate--the marmoset. 751 39

The relationship among "negative" plasma acute-phase proteins (APP), ie, albumin, prealbumin, and transferrin, and "positive" APP, ie, C-reactive protein (CRP), fibrinogen, and orosomucoid, was investigated in patients with acute infectious disease (n = 8) and in patients with chronic malignant disease (n = 9). In addition, the transcapillary escape rate (TER) and outflux (J(alb)) of albumin were investigated using an intravenous injection of 2 microCi 125I-albumin. Interleukin-6 (IL-6) plasma concentrations were measured with an enzyme immunoassay. In the majority of patients, negative APP were decreased, whereas positive APP were increased. However, in patients with infectious disease, there were no significant correlations between any of the negative and positive APP. Also, in patients with infectious disease, TER was increased to 8.6 +/- 3.4%/h (mean +/- SD), and J(alb) to 114 +/- 60 mg/kg/h, compared with normal values of 4.3 +/- 2.6%/h and 108 +/- 7 mg/kg/h, respectively. Unexpectedly, there was a significant positive correlation between plasma albumin and both TER (r = .8279, P = .011) and J(alb) (r = .8683, P = .005). In patients with malignomas, significant correlations within negative and positive APP and inverse correlations between negative and positive APP resulted. Malignant disease induced only a slight elevation in TER (6.6 +/- 2.4%/h), J(alb) was within normal limits (92 +/- 35 mg/kg/h), and no correlations between plasma albumin concentrations and TER (r = -.0174, P = .97) or J(alb) (r = .4090, P = .27) were found.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transcapillary escape rate of albumin positively correlates with plasma albumin concentration in acute but not in chronic inflammatory disease. 751 58

In the present study, interleukin-6 (IL-6) and several acute phase proteins were measured in healthy participants (23-87 years of age). A linear correlation between IL-6 and age was established with an increase of 0.016 pg/ml (0.004) per year of life. Whereas CRP remained below 0.5 mg/dl in all participants, an increase with age for fibrinogen and an inverse relation for albumin as well as transferrin were obtained. However, the increase of IL-6 did not correlate with any of these changes. IL-6 associated diseases may therefore occur more often with advancing age, but in healthy participants IL-6 does not explain the changing plasma protein pattern resembling that of an acute phase reaction.
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PMID:Interleukin-6 and selected plasma proteins in healthy persons of different ages. 753 83

The regulation of acute-phase protein production and nitric oxide (NO) release in lipopolysaccharide-induced liver injury is thought to occur in response to monocytes/macrophages and Kupffer-cell-derived cytokines. In this study, we used primary cultured rat hepatocytes maintained as a differentiated phenotype to investigate the direct effects of endotoxin (lipopolysaccharide) on the production of the acute-phase proteins and on NO release. Lipopolysaccharide (10 micrograms/ml) increased the production of alpha 2-macroglobulin 2.5-fold compared to untreated cultures and decreased the production of albumin by 50%. The effect of lipopolysaccharide was mimicked by adding interleukin-6 (IL-6) and tumor-necrosis factor alpha (TNF-alpha), cytokines being induced by treatment of hepatocytes with lipopolysaccharide. Maximal TNF-alpha (600 pg/ml) and IL-6 (1800 pg/ml) concentrations were observed 4 h and 6 h after lipopolysaccharide stimulation, respectively. The lipopolysaccharide-induced acute-phase protein response was blocked by anti-(IL-6) but not by anti-(TNF-alpha) IgG. The latter reduced the lipopolysaccharide-induced IL-6 production by 60%. Besides its effects on the acute-phase proteins, endotoxin caused a significant increase in NO production in cultured rat hepatocytes. Unlike anti-(IL-6) IgG, anti-(TNF-alpha) IgG reduced the lipopolysaccharide-induced NO production by 50% indicating that endotoxin-induced NO production is partially mediated by TNF-alpha but not by IL-6. Preculture with gadolinium chloride (GdCl3), an inhibitor of Kupffer cells, did not change the response of hepatocytes to lipopolysaccharide indicating that the observed findings are direct endotoxin effects on hepatocytes. The data demonstrate that by their production of TNF-alpha and IL-6 rat hepatocytes respond to lipopolysaccharide treatment with an IL-6 mediated acute-phase protein and a TNF-alpha-mediated NO production. These features have previously been attributed to monocytes/macrophages and Kupffer cells.
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PMID:Hepatocyte-derived interleukin-6 and tumor-necrosis factor alpha mediate the lipopolysaccharide-induced acute-phase response and nitric oxide release by cultured rat hepatocytes. 753 77

Studies were performed in Hep3B hepatocytes to better elucidate the mechanisms regulating circulating levels of human group-specific component (Gc). We measured changes in Gc messenger RNA (mRNA) synthesis and levels of secreted protein resulting from treatment of hepatocytes with cytokines and hormones known to influence synthesis of other proteins of hepatic origin. We particularly focused on compounds known to be prototypic stimulants during the acute phase response. Interleukin-6 (IL-6) and dexamethasone were shown to increase Gc mRNA approximately twofold while transforming growth factor beta (TGF beta) decreased Gc mRNA in a dose-dependent fashion by up to fivefold. The effects on secreted Gc protein levels were similar. These results indicate that Gc protein appears to be regulated differently than the other members of this gene family, albumin and alpha-fetoprotein (AFP), which are negative acute phase reactants. In addition, these contrasting effects on Gc synthesis of IL-6 and dexamethasone and of TGF beta suggest that high basal levels of Gc synthesis may be maintained during the acute phase response.
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PMID:Regulation of human Gc (vitamin D--binding) protein levels: hormonal and cytokine control of gene expression in vitro. 753 97

We hypothesized that increased levels of blood cytokines occur in brain-dead patients, and that these cytokines are responsible for some of the endocrine and/or acute-phase reactant abnormalities found in these patients. We measured blood levels of cytokines, hormones, and acute-phase reactants in 18 brain-dead potential organ donors at the moment of establishing the legal diagnosis of brain death and compared them with levels found in a control group. Although interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) levels were within the normal range, interleukin-6 (IL-6) levels were clearly above the normal range in all patients (median, 1,444 pg/mL; range, 75 to 11,780). In the brain-dead group, total thyroxine (tT4), free T4 (fT4), triiodothyronine (T3), thyrotropin (TSH), dehydroepiandrosterone sulfate (DHEA-S), testosterone, albumin, Zn, and osteocalcin levels were decreased, T3 resin uptake index (T3 RUI), corticotropin (ACTH), cortisol, 11-deoxycortisol (11-DOC), 17-hydroxyprogesterone (17-OHPr), aldosterone, luteinizing hormone, and follicle-stimulating hormone levels were normal, and reverse T3 (rT3), renin, and C-reactive protein (CRP) levels were increased. Multiple regression analysis demonstrated significant interrelations between IL-6 and T4, T3, testosterone, and CRP. We also studied the evolution of some of these parameters in four patients with severe head injury who finally developed brain death. IL-6 levels on admission to the intensive care unit (ICU) were above the normal limits, as in other patients with cranial trauma, but when the patients developed brain death, there was a pronounced increase in IL-6 levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Blood levels of cytokines in brain-dead patients: relationship with circulating hormones and acute-phase reactants. 754 Feb 49

The effects of nicotinamide on hepatocyte viability and secretion of albumin and alpha 1-acid glycoprotein were studied in the absence or presence of dexamethasone and/or recombinant human interleukin-6 either after cell attachment (2 h) or after 24, 48, and 72 h of culture. The evolution of hepatocyte survival during the culture was appreciated by measurement of total DNA content. The secretion of albumin and alpha 1-acid glycoprotein was measured after a 4-h period following cell attachment or after 24, 48 and 72 h of culture. The important decrease of DNA content, mRNA levels and secretion of albumin and alpha 1-acid glycoprotein in control cultures after 2-3 days was not prevented by the addition of nicotinamide. In contrast, dexamethasone alone or with recombinant human interleukin-6 improved DNA content and albumin secretion with no additional effect of nicotinamide. The secretion of alpha 1-acid glycoprotein was largely induced by dexamethasone alone or dexamethasone and recombinant human interleukin-6. The increase of alpha 1-acid glycoprotein secretion was not modified by the addition of nicotinamide and averaged respectively 27- and 60-fold for dexamethasone alone and dexamethasone and recombinant human interleukin-6 after 48 h. These observations suggested that nicotinamide, at least in the conditions tested here, is unable to prevent alterations of hepatocyte viability and gene expression of cultured hepatocytes.
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PMID:Effects of nicotinamide on hepatocyte viability and secretion of albumin and alpha 1-acid glycoprotein by adult rat hepatocytes in primoculture. Comparison with dexamethasone and recombinant human interleukin-6. 754 7


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