Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During inflammation a number of liver-derived plasma proteins increases in concentration. In the rat these so-called acute-phase proteins are mainly proteinase inhibitors, such as alpha 1-proteinase inhibitor, alpha 1-acute-phase globulin and alpha 2-macroglobulin. At present, the mechanisms responsible for the enhanced synthesis of acute-phase proteins are poorly understood. Therefore, we have studied the induction of alpha 2-macroglobulin synthesis in rat hepatocyte primary cultures. Adrenaline, triiodothyronine, estradiol and progesterone were tested for their ability to stimulate alpha 2-macroglobulin synthesis. Only triiodothyronine induced alpha 2-macroglobulin synthesis markedly. However, the presence of dexamethasone was a prerequisite for alpha 2-macroglobulin induction indicating a permissive action of glucocorticoids. Besides glucocorticoids and triiodothyronine a non-dialyzable factor (HSF) derived from rat Kupffer cells or human peripheral blood monocytes was found to be able to stimulate alpha 2-macroglobulin synthesis in hepatocytes. Equal amounts of HSF activity were found in conditioned media from lipopolysaccharide-stimulated and unstimulated rat Kupffer cells as well as in human monocytes. Since the supernatants of unstimulated rat Kupffer cells or human monocytes did not exhibit interleukin 1 activity, HSF activity distinct from interleukin 1 must exist. No HSF activity was found in media conditioned by rat Kupffer cells which had been treated with dexamethasone. Hepatocyte primary cultures were incubated with [35S]methionine-labeled proteins secreted by rat Kupffer cells. A 30 kDa polypeptide was found to be bound to or internalized by rat hepatocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The acute-phase induction of alpha 2-macroglobulin in rat hepatocyte primary cultures: action of a hepatocyte-stimulating factor, triiodothyronine and dexamethasone. 242 35

Incorporation of [3H]leucine into haptoglobin and albumin by isolated rat hepatocyte suspensions was studied to assess the role of potential mediators of the acute-phase reaction in promoting haptoglobin synthesis. In vitro, in the presence of insulin, the addition of a hormone mixture containing hydrocortisone, glucagon, somatotropin, and triiodothyronine resulted in a 70% increase in leucine incorporation into haptoglobin relative to albumin at 48 h incubation. A variety of agents, selected because they are considered to play some part in the acute-phase reaction, were added to the medium, and similar measurements of leucine incorporation were made. The specific binding to hepatocytes by asialo- and asialo, agalacto-derivatives of haptoglobin or orosomucoid did not affect synthesis of haptoglobin or albumin. Epinephrine, prostaglandins E1 and E2, bacterial lipopolysaccharide, and sera containing active complement components also failed to stimulate relative haptoglobin synthesis. A partially purified preparation of human leukocytic pyrogen, however, caused a 70% increase in leucine incorporation into haptoglobin relative to albumin in the present of the hormone mixture, suggesting that this substance may affect acute-phase protein synthesis.
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PMID:Haptoglobin and albumin synthesis in isolated rat hepatocytes. Response to potential mediators of the acute-phase reaction. 701 8

1. Male Sprague-Dawley or Wistar rats were injected with bacterial lipopolysaccharide (LPS; 5 mg kg-1, i.p.) and killed after 1, 3, 6, 15, and 24 h. The brains, mesenteries, spleens, lungs, livers, kidneys, hearts, aortae and diaphragms were removed and frozen immediately. Control rats were injected with sterile saline and killed after 6 h. 2. The organs were homogenized in a semi-frozen state and NO synthase (NOS) activity measured in tissues from both LPS-treated and saline-treated groups by the ability of homogenates to convert [3H]-L-arginine to [3H]-L-citrulline in a NADPH-dependent manner. 3. The NOS activity in all organs taken from control animals was found to be calcium-dependent, with the highest activity being in the brain. After LPS-treatment an induced calcium-independent NOS was detected in all tissues tested, with the exception of the brain. The spleen, lung, mesentery and liver had the highest amounts of LPS-induced NOS activity. No induction of calcium-dependent NOS was detected. 4. Induction of NOS was maximum 6 h after administration of LPS and had returned to control levels in 24 h. 5. The constitutive NOS in brain and mesentery and the LPS-induced activities in the spleen, lung, liver and mesentery were inhibited by NG-monomethyl-L-arginine (L-NMMA) or NG-nitro-L-arginine methyl ester (L-NAME) according to concentration. The IC50 for L-NAME was 2.5 microM against the constitutive NOS from brain, and 20-25 microM against the inducible NOS. For L-NMMA the IC50 was 20-25 microM against either NOS isoform. 7. The vascular responses to endothelin-I (ET-1), the thromboxane A2-mimetic 11 alpha,9 alpha-epoxymethanoprostaglandin F2alpha (U46619), phenylephrine (PE) or 5-hydroxytryptamine (5-HT) were measured in the simultaneously perfused arterial and venous mesenteric vascular beds from both control and LPS-treated(6 h) rats. Vasoconstrictor responses to all agonists tested were unaffected by LPS treatment. In the presence of L-NAME (100 microM) vasoconstrictor responses were potentiated in both the arterial and venous portion of the mesenteric beds from both control and LPS-treated rats. The potentiation of responses to U46619 was significantly greater in beds from LPS-treated rats.8. Injection of LPS i.p. is associated with induction of NOS in all organs tested, except for the brain. In the mesentery this is not accompanied by a hyporesponsiveness to constrictor agents suggesting an increased sensitivity, particularly to U46619. This may explain the poor perfusion and tissue damage in the splanchnic circulation associated with sepsis.
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PMID:Induction by endotoxin of nitric oxide synthase in the rat mesentery: lack of effect on action of vasoconstrictors. 768 6

A bidirectional communication exists between the nervous system and the immune system. Evidence has accumulated suggesting that cytokines-immune peptides influence sympathetic neuronal survival and that cytokines can promote the secretion of catecholamines. Using an isolated perfused rat liver (IPRL) preparation, we have shown that the liver is an important source of circulating cytokines in response to lipopolysaccharide (LPS) and that corticosterone dose dependently influenced LPS-induced production of tumor necrosis factor (TNF) and interleukin-6 (IL-6). In this study, we investigated the direct effect of epinephrine (another stress hormone) on the production of TNF and IL-6 in liver. We demonstrated that epinephrine (1 microM/ml) alone did not induce TNF bioactivity but significantly increased IL-6 bioactivity from IPRL effluent. When the IPRL was infused with LPS, epinephrine significantly decreased TNF bioactivity. Epinephrine in LPS-treated livers also significantly increased IL-6 bioactivity. Both responses were totally inhibited by the beta-blocker propranolol (10 microM/ml). Anisomycin, a protein synthesis inhibitor, infused into the IPRL completely blocked the rise in TNF and IL-6 concentrations in the effluent leaving the IPRL, supporting the hypothesis that the synthesis (or release) of these cytokines was dependent on protein synthesis. We then attempted to determine whether epinephrine exerts similar effects in vitro. Using isolated Kupffer cells and hepatocytes, we found that epinephrine alone had no effect on TNF and IL-6 production in Kupffer cells and hepatocytes but significantly decreased LPS-induced TNF bioactivity and increased LPS-induced IL-6 bioactivity in Kupffer cells. Our data support the hypothesis that epinephrine can promote IL-6 secretion from IPRL.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of epinephrine in TNF and IL-6 production from isolated perfused rat liver. 773 99

Adrenaline has been shown to inhibit the release of tumor necrosis factor (TNF) elicited by lipopolysaccharide (LPS) when tested in vitro on cultured human blood cells and rat macrophages. In this report we have examined the effect of the in vivo administration of adrenaline on TNF serum levels induced by LPS. In agreement with in vitro data, adrenaline (0.1 mg/kg, s.c.) was found to inhibit in the mouse the LPS-induced TNF release. The beta-adrenergic antagonist propranolol administered 1 h before adrenaline completely blocked the adrenaline activity, whereas the alpha-adrenergic antagonist phentolamine was ineffective. These data demonstrate that: (i) adrenaline is an effective antagonist of LPS-induced TNF release in vivo, and (ii) its effect is mediated by beta-adrenergic receptors.
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PMID:Beta-adrenergic receptors mediate in vivo the adrenaline inhibition of lipopolysaccharide-induced tumor necrosis factor release. 829 40

Epinephrine inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) production by increasing intracellular cAMP concentrations. Because agents that increase cAMP levels can enhance TNF receptor expression in vitro, granulocyte and monocyte TNF receptors were determined by FACS-analysis in 7 normal humans who were receiving a constant 24-h infusion of epinephrine (30 ng/kg/min), and in 15 normal subjects after intravenous injection of LPS (2 ng/kg), while they were receiving a continuous infusion of epinephrine started either 3 h (EPI-3) or 24 h (EPI-24) before LPS injection or an infusion of normal saline (LPS; n = 5 per group). Infusion of epinephrine per se did not influence TNF receptor expression. LPS induced a transient decrease in monocyte TNF receptors and a more sustained decrease in granulocyte TNF receptors (both P < 0.05). EPI-3 partly prevented LPS-induced down-modulation of monocyte TNF receptors (P < 0.05 vs. LPS only), but did not affect LPS-induced down-modulation of granulocyte TNF receptors. EPI-24 had no effect on TNF receptor expression. These data suggest that epinephrine not only influences the bioavailability of TNF by an effect on the production of this proinflammatory cytokine, but also by modulating the expression of its receptors.
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PMID:Epinephrine attenuates down-regulation of monocyte tumor necrosis factor receptors during human endotoxemia. 902 20

To determine the effect of a physiologically relevant elevation in the plasma concentrations of epinephrine on the activation of the hemostatic mechanism during endotoxemia, 17 healthy men were studied after intravenous injection of lipopolysaccharide (LPS, 2 ng/kg), while receiving a continuous infusion of epinephrine (30 ng/kg/min) started either 3 h (n = 5) or 24 h (n = 6) before LPS injection, or an infusion of normal saline (n = 6). Activation of the coagulation system (plasma concentrations of thrombin-antithrombin III complexes and prothrombin fragment F1+2) was significantly attenuated in the groups treated with epinephrine when compared with subjects injected with LPS only (P <0.05). Epinephrine enhanced LPS-induced activation of fibrinolysis (plasma levels of tissue-type plasminogen activator and plasmin-alpha2-antiplasmin complexes; P <0.05), but did not influence inhibition of fibrinolysis (plasminogen activator inhibitor type I). In subjects infused with epinephrine, the ratio of maximal activation of coagulation and maximal activation of fibrinolysis was reduced by >50%. Hence, epinephrine exerts antithrombotic effects during endotoxemia by concurrent inhibition of coagulation, and stimulation of fibrinolysis. Epinephrine, whether endogenously produced or administered as a component of treatment, may limit the development of disseminated intravascular coagulation during systemic infection.
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PMID:Epinephrine exerts anticoagulant effects during human endotoxemia. 909 88

To determine the effect of epinephrine and hydrocortisone on lipopolysaccharide (LPS)-induced interleukin 8 (IL-8) production, human whole blood was stimulated with LPS in the presence or absence of these stress hormones. Epinephrine caused a dose-dependent increase in LPS-induced IL-8 production, which was mediated exclusively via beta-adrenergic receptors, as reflected by the facts that beta (but not alpha) receptor blockade reversed the epinephrine effect and beta (but not alpha) receptor stimulation reproduced the epinephrine effect. Further, elevating cellular cyclic AMP (cAMP) concentrations, a known effect of beta-adrenergic stimulation, by addition of dibutyryl cAMP also enhanced LPS-induced IL-8 production. Epinephrine-induced upregulation of IL-10 production masked an even more pronounced stimulating effect of this hormone on IL-8 synthesis, as indicated by the finding that the extent of IL-8 upregulation was greater in the presence of anti-IL-10 than in the absence of anti-IL-10. Hydrocortisone dose-dependently inhibited LPS-induced IL-8 production and reversed epinephrine-induced enhancement of IL-8 production. Epinephrine and hydrocortisone have opposite effects on IL-8 production, which may be relevant for the understanding of endogenous and therapeutic stress hormone influences on IL-8 mediated inflammation.
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PMID:Lipopolysaccharide-induced interleukin 8 production by human whole blood is enhanced by epinephrine and inhibited by hydrocortisone. 916 77

Tumor necrosis factor (TNF) is involved in the pathogenesis of acute sepsis-induced organ injury and has been implicated as a mediator of metabolic alterations observed during sepsis. Pancreatic islet cell function may be significantly compromised during sepsis or endotoxemia, and sepsis also increases plasma levels of epinephrine, a modifier of islet insulin secretion. We proposed that islets exposed to bacterial lipopolysaccharide (LPS) produce TNF and that epinephrine attenuates islet secretory activity. We monitored the effects of LPS and epinephrine on TNF and insulin activity of isolated Wistar-Furth rat islets (pancreas digested with collagenase, islets isolated using Ficoll gradients; n = 4 islet populations, each with 632 +/- 11 islets/2.5 ml culture medium). Islets were incubated (37 degrees C, 5% CO2) 3 days. LPS (Escherichia coli, 1 microgram/ml) and epinephrine (14 micrograms/ml) were added to the islets, and incubations were continued for 1-4 h. Glucose (Beckman Glucose Analyzer), insulin (radioimmunoassay), and TNF (L929 cytotoxicity assay) were measured in the islet medium samples at 1- to 4-h time points. In the conditioned medium, glucose decreased (P < 0.05), insulin increased (P < 0.05), and exposure to LPS did not alter these levels [P = not significant (NS)] but did increase TNF activity by 400% (P < 0.05). Epinephrine reduced insulin by 38-43% (P < 0.05) and TNF by 20-25% (P < 0.05) but had no effect on glucose levels (P = NS). We conclude that insulin is secreted from isolated islets and that exposure to LPS acutely increases islet-derived TNF activity, whereas epinephrine modifies TNF and insulin secretion of rat pancreatic islets.
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PMID:Tumor necrosis factor activity of pancreatic islets. 927 98

Epinephrine has been found to inhibit the production of the proinflammatory cytokine tumor necrosis factor (TNF)-alpha and to enhance the production of anti-inflammatory cytokine interleukin (IL)-10. To determine the effect of epinephrine on IL-1 beta production, the following experiments were performed: 1) blood obtained from subjects at 4-21 h after the start of a continuous infusion of epinephrine (30 ng.kg-1.min-1) produced less IL-1 beta after ex vivo stimulation with lipopolysaccharide (LPS), compared with blood drawn from subjects infused with saline; 2) in whole blood in vitro, epinephrine caused a dose-dependent decrease in LPS-induced IL-1 beta production, which was likely mediated via adrenergic receptors; and 3) inhibition of TNF and enhancement of IL-10 both contributed to epinephrine-induced inhibition of IL-1 beta production. Epinephrine, either endogenously produced or administered as a component of sepsis treatment, may attenuate excessive activity of proinflammatory cytokines early in the course of systemic infection.
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PMID:Epinephrine inhibits endotoxin-induced IL-1 beta production: roles of tumor necrosis factor-alpha and IL-10. 943 41


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