Cellular targets and receptors for interleukin-6 II. Characterization of IL-6 binding and receptors in peripheral blood cells and macrophages

Within 15 min, approximately 2.5% of 125I-labelled interleukin-6 (IL-6) injected intravenously into rats was taken up by the spleen. As determined by light microscopic autoradiography, uptake was mainly (60%) accounted for by macrophages in the red pulp. 125I-IL-6 binding in rat peritoneal macrophages was quantitatively similar to that in cultured human monocytes and T-cells. By comparison, IL-6 binding to polymorphonuclear granulocytes and freshly isolated monocytes was low. Stimulation with antigen, but not with mitogen (PWM), induced receptor presentation in B-cells, whereas antigen and mitogen downregulated the binding in T-cells. At 4 degrees C, labelled IL-6 bound to cells with a half-time of about 1.5 h. Binding appeared reversible, but dissociation was slow and incomplete. The apparent Kd for IL-6 binding was about 30 pmol l-1 in most cell types, however, values of approximately 120 pmol l-1 were obtained in polymorphonuclear granulocytes. At 37 degrees C, 125I-IL-6 was rapidly internalized by T-cells and monocyte-macrophages, and after a lag time, TCA-soluble radioactivity was released from the cells following a sigmoidal curve. Polyacrylamide gel electrophoresis of radiolabelled IL-6 cross-linked to its binding sites in T-cells, yielded receptor-ligand complexes with molar masses of 70-80 and 120-140 kg mol-1. This would agree with a dimeric conformation of the IL-6 receptor.     

Degradation of vasoactive intestinal peptide by isolated, ventilated, and perfused rat lungs

The degradation of vasoactive intestinal peptide (VIP) was studied using an isolated perfused rat lung model. 125iodine labelled VIP (125I-VIP) was used as a tracer. VIP was cleared from the perfusate by a single lung passage up to concentrations of 1 nmol l-1. The clearance rate was decreased at higher concentrations of VIP. VIP was taken up by the lung tissue and the cleavage products were re-extruded into the perfusate. The time delay of re-extrusion was increased at starting concentrations of VIP exceeding 1 nmol l-1 and in the presence of the lysosomal inhibitor chloroquine. After a bolus of 9 pmol or 40 nmol 125I-VIP into the pulmonary artery catheter 6.3 pmol or 2920 pmol, respectively, were bound by the lung. Most of the radioactive material was extruded within 25 min and consisted of low molecular weight 125I-labelled degradation products. We conclude that the receptors for VIP in the alveolar capillaries are of high affinity and capacity to extract VIP from the circulation and that lysosomes may be involved in the degradation. The degradation products are of low molecular weight.     

重组人EPO对rhIL-6诱导HepG2细胞和人原代肝细胞Hepcidin mRNA表达的抑制作用

本研究探讨EPO对人肝细胞株和原代肝细胞Hepcidin表达的影响和rhEPO在慢性病贫血治疗方面的机制。在HepG2人肝癌细胞及人原代肝细胞培养液中加入不同浓度的rhIL-6、rhEPO并作用不同时间。提取mRNA，行RT—PCR后进行紫外荧光显像，以Hepcidin与G3PDH的mRNA比值进行半定量分析；比较不同条件下人原代肝细胞及肝肿瘤细胞Hepcidin的表达水平。结果表明：rhIL-6能刺激HepG2细胞和人原代肝细胞Hepcidin mRNA表达升高，rhEPO对IL-6刺激Hepcidin mRNA表达有抑制作用，单纯rhEPO对HepG2细胞Hepcidin表达基本无影响。结论：重组人IL-6能刺激HepG2细胞和人原代肝细胞Hepcidin mRNA表达升高，并在一定范围内呈时间、剂量依赖效应．rhEPO对这一作用有抑制作用。     

过敏性哮喘外周血细胞因子白细胞介素2、白细胞介素6及其受体的测定和临床意义

目的　动态检测过敏性哮喘外周血血浆中白细胞介素 2 (IL 2 )、白细胞介素 6(IL 6)及其受体 (IL - 2R、IL - 6R)的变化 ,探讨其在哮喘中的作用。方法　采用间接荧光标记、流式细胞仪和酶联免疫夹心法 (ELSA)进行表型及定量分析。结果　过敏性哮喘急性发作期外周血血浆中IL 2、IL 6及其可溶性受体皆升高 (P <0 .0 1) ,至缓解期也未恢复至正常范围 ;膜型白细胞介素 2受体 [mIL 2R ,即白细胞相关抗原 (CD2 5 ) ]在各期均无变化。结论　IL 2、IL 2R、IL 6、IL 6R参与了哮喘的发生、发展 ,动态观察有助于病情评估 ,同时提示哮喘患者缓解期气道炎症仍持续存在     

How does interleukin-6 affect the membrane expressions of interleukin-6 receptor and gp130 and the proliferation of the human myeloma cell line OPM-2?

Interleukin-6 (IL-6) is a potent growth factor for the proliferation of multiple myeloma (MM), which accounts for 1-2% of all human cancers. In this study we investigated the effects of IL-6 in various doses on the following parameters in the human myeloma cell line OPM-2: membrane expression of IL-6 receptor (IL-6R) and gp130, proliferation of the tumour cells and the amount of the soluble IL-6 receptor (sIL-6R) in the supernatant. Additionally, we tested the same parameters with the immunomodulator Viscum album (VA) extract. The expression of surface IL-6R and gp130 was analysed by FACS, the measurements of proliferation using the BrdU incorporation during DNA synthesis, and the determination of sIL-6R in the supernatant by ELISA. OPM-2 cells proliferate spontaneously (doubling time: 48 h), IL-6-production was not detectable. The exogenous IL-6 upregulated its own receptor up to a mean of 180% of controls at 5 ng/ml (P < 0.001), higher or lower doses were less effective. The membrane expression of gp130 was downregulated to 1-2%. IL-6 led to increase of the sIL-6R in the supernatant (P < 0.001) and raised the proliferation of the myeloma cells up to a mean of 124% (P < 0.001). These results indicate that the human myeloma cell line OPM-2 has an autocrine IL-6 regulation mechanism, with an additional paracrine signalling by exogenous IL-6. This is the first report that IL-6 inhibits the membrane expression of gp130, although the proliferation of the myeloma cells increases. VA extract did not affect survival, the expression of surface receptors IL-6 and gp130 or the amount of sIL-6R in the supernatant. However, the proliferation of the tumour cells was inhibited significantly (P < 0.05) suggesting a possible arrest in the cell cycle.     

Interferon beta 2/interleukin 6 modulates synthesis of alpha 1-antitrypsin in human mononuclear phagocytes and in human hepatoma cells.

The cytokine IFN beta 2/IL-6 has recently been shown to regulate the expression of genes encoding hepatic acute phase plasma proteins. INF beta 2/IL-6 has also been shown to be identical to MGI-2, a protein that induces differentiation of bone marrow precursor cells toward mature granulocytes and monocytes. Accordingly, we have examined the effect of IFN beta 2/IL-6 on expression of the IL-1- and tumor necrosis factor-unresponsive acute phase protein alpha 1-antitrypsin (alpha 1 AT) in human hepatoma-derived hepatocytes and in human mononuclear phagocytes. Purified human fibroblast and recombinant IFN beta 2/IL-6 each mediate a specific increase in steady-state levels of alpha 1 AT mRNA and a corresponding increase in net synthesis of alpha 1 AT in primary cultures of human peripheral blood monocytes as well as in HepG2 and Hep3B cells. Thus, the effect of IFN beta 2/IL-6 on alpha 1 AT gene expression in these cells is primarily due to an increase in accumulation of alpha 1 AT mRNA and can be distinguished from the direct, predominantly translational effect of bacterial lipopolysaccharide on expression of this gene in monocytes and macrophages. The results indicate that IFN beta 2/IL-6 regulates acute phase gene expression, specifically alpha 1 AT gene expression, in extrahepatic as well as hepatic cell types.     

IL-6在视网膜脱离及复位状态下的表达

目的 探讨IL-6在视网膜脱离及复位状态下的表达。方法 在SD大鼠视网膜下注入Healon GV (1．4％透明脂酸钠)制备视网膜脱离模型。放免检测脱离后不同时间点及复位后神经网膜的IL-6蛋白含量，并通过免疫组化定位IL-6的表达。应用图象分析系统分析脱离区、未脱离区及复位区色素上皮IL-6表达的差异，并对不同脱离状态的视网膜进行组织病理学分析。结果 单纯色素上皮与神经网膜脱离引起网膜下的增殖，增殖在脱离后第10d达到高峰，然后下降；IL-6在色素上皮及神经网膜都有表达，神经网膜的表达在视网膜复位后下降；脱离区色素上皮IL-6的表达比未脱离区明显增高。结论 IL-6积极参与了色素上皮与神经网膜脱离后的损伤修复反应；视网膜的复位可以降低IL-6的表达。     

IgA肾病患者扁桃体切除前后血、尿IL-2、IL-6的变化

目的检测IgA肾病患者扁桃体切除前后患者的血、尿IL-2、IL-6的水平,以探讨其变化规律和临床意义。方法选取经肾活检诊断为IgA肾病的患者76例,并排除肝硬化等继发性IgA肾病,并根据系膜增生程度分为轻度系膜增生组(A组)62例,中度系膜增生组(B组)5例,中度系膜增生伴新月体形成(C组)5例、局灶节段硬化组(D组)4例,同时选取健康查体10人作正常对照组(E组),观察患者扁桃体切除术前、术后6个月时患者的血尿IL-2、IL-6的水平。结果轻、中度系膜增生组扁桃体切除半年后尿IL-2、血IL-6、尿IL-6含量明显低于扁桃体切除前,结果有显著性差异(T=1.9624-9.6436、P0.05),而中度系膜增生伴新月体形成组和局灶节段硬化组两组患者扁桃体切除前和切除半年后血清及尿IL-2、IL-6较前下降,但无统计学意义(t=0.3221-1.0914)。无论扁桃体切除前后C、D两组患者的尿IL-2、IL-6水平均明显高于A、B组患者,二者有统计学差异(T2.235 5,P0.01)。结论轻、中度系膜增生性IgA肾病患者行扁桃体切除能改善患者的炎症因子的产生,降低患者尿IL-2、IL-6水平,而对于中度系膜增生伴新月体形成和局灶节段硬化的患者来说,扁桃体切除意义不大;对于尿液中IL-2、IL-6水平持续处于高水平的患者,提示病理损伤较重,扁桃体切除的意义不大。     

Stimulation of Lipogenesis by Interleukin-6 and Misoprostol-Free Acid in Isolated Rat Hepatocytes

Recent work has established that Kupffer cell products, including prostaglandins, can act directly on hepatocytes to modify glucose and lipid metabolism. Additionally, prostaglandins can act on Kupffer cells to modify the expression of cytokines. Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) stimulate hepatic lipogenesis following in vivo administration. To define the direct effects of these cytokines on lipogenesis in primary culture rat hepatocytes, hepatocytes were cultured in the presence of IL-6 or TNF-alpha for periods of 24--72 h. IL-6 caused an increase in hepatocyte lipogenic capacity (56% increase by 12.5 ng ml(minus sign1) IL-6 after 72 h of cytokine exposure). The increase in cellular lipogenic capacity was confirmed using (3)H2O as the radiotracer. TNF-alpha did not increase the rate of hepatocyte lipogenesis. Neither IL-6 nor TNF-alpha modified rates of lipogenesis upon acute exposure to the cytokine. Misoprostol-free acid (0.1 &mgr;M) acutely increased hepatocyte lipogenic rates by 14% in the presence of glucagon. These results demonstrate that IL-6 can act directly on hepatocytes to induce lipogenic capacity and that E-series prostaglandins can antagonize the acute inhibition of lipogenesis by glucagon. Because IL-6 is produced by Kupffer cells, and its expression is modulated by prostaglandins, the Kupffer cell is a novel target for prostaglandin therapy. Administration of prostaglandins may provide a novel strategy for pharmacologic therapy of disorders of glucose or lipid metabolism.     

The specific binding of thrombin to human polymorphonuclear leucocytes

Thrombin is a chemotaxin for polymorphonuclear leucocytes. In this paper the binding kinetics of 125I-labelled thrombin to purified polymorphonuclear leucocytes is characterized. At 4 degrees C, the 125I-labelled thrombin bound to the cells with a half-time of about 3 min. About 0.77 of the bound tracer dissociated upon addition of a surplus of unlabelled thrombin or hirudin. Each cell possessed about 50 receptors with a Kd of 18 pmol/l and about 6000 receptors with a Kd of 31 nmol/l. Although the binding affinity at 37 degrees C was 7-10-fold lower than that measured at 4 degrees C, it may be high enough to constitute the molecular basis for the reported thrombin-induced chemotaxis.     

Pharmacology of beta-L-thymidine and beta-L-2'-deoxycytidine in HepG2 cells and primary human hepatocytes: relevance to chemotherapeutic efficacy against hepatitis B virus

beta-L-Thymidine (L-dT) and beta-L-2'-deoxycytidine (L-dC) are potent and highly specific inhibitors of hepatitis B virus (HBV) replication both in vivo and in vitro (50% effective concentrations, 0.19 to 0.24 microM in 2.2.15 cells). The intracellular metabolisms of L-dT and L-dC were investigated in HepG2 cells and primary cultured human hepatocytes. L-dT and L-dC were extensively phosphorylated in both cell types, with the 5'-triphosphate derivative being the predominant metabolite. In HepG2 cells, the 5'-triphosphate levels were 27.7 +/- 12.1 and 72.4 +/- 1.8 pmol/10(6) cells for L-dT and L-dC, respectively. In primary human hepatocytes, the 5'-triphosphate levels were 16.5 +/- 9.8 and 90.1 +/- 36.4 pmol/10(6) cells for L-dT and L-dC, respectively. Furthermore, a choline derivative of L-dCDP was detected at concentrations of 15.8 +/- 1.8 and 25.6 +/- 0.1 pmol/10(6) cells in human hepatocytes and HepG2 cells, respectively. In HepG2 cells exposed to L-dC, the 5'-monophosphate and 5'-triphosphate derivatives of beta-L-2'-deoxyuridine (L-dUMP and L-dUTP, respectively) were also observed, reaching intracellular concentrations of 6.7 +/- 0.4 and 18.2 +/- 1.0 pmol/10(6) cells, respectively. In human hepatocytes, L-dUMP and L-dUTP were detected at concentrations of 5.7 +/- 2.4 and 43.5 +/- 26.8 pmol/10(6) cells, respectively. It is likely that deamination of L-dCMP by deoxycytidylate deaminase leads to the formation of L-dUMP, as the parent compound, L-dC, was not a substrate for deoxycytidine deaminase. The intracellular half-lives of L-dTTP, L-dCTP, and L-dUTP were at least 15 h, with intracellular concentrations of each metabolite remaining above their respective 50% inhibitory concentrations for the woodchuck hepatitis virus DNA polymerase for as long as 24 h after removal of the drug from cell cultures. Exposure of HepG2 cells to L-dT in combination with L-dC led to concentrations of the activated metabolites similar to those achieved with either agent alone. These results suggest that the potent anti-HBV activities of L-dT and L-dC are associated with their extensive phosphorylation.     

白细胞介素-6及其受体在子宫肌瘤的表达及意义

目的 研究白细胞介素-6(IL-6)与IL-6受体(IL-6R)在子宫肌瘤的表达及意义.方法 选择因子宫肌瘤行子宫全切除的患者20例,对于子宫肌瘤和同源正常子宫平滑肌,分别采用western blot和荧光定量PCR检测IL-6的表达;western blot和RT-PCR检测IL-6R的表达.结果 IL-6蛋白和mRNA在正常子宫平滑肌表达明显高于子宫肌瘤[(0.7996±0.0359)比(0.6904±0.0414)和(0.0470 ±0.0071)比(0.0283±0.0045)],差异均有统计学意义(P均＜0.05);而IL-6R蛋白和mRNA表达在肌瘤与平滑肌间差异无统计学意义[(0.7105±0.0520)比(0.6904±0.0532)和(0.6644±0.0537)比(0.6465±0.0501),P均＞0.05)].结论 子宫肌瘤局部IL-6低表达可能在一定程度上参与肌瘤的发病,而IL-6R未参与子宫肌瘤发病.     

肺移植术后受者T细胞亚群和IL-6水平的动态变化1例并文献分析

目的：探讨肺移植术后患者T细胞亚群和白介素-6（IL-6）水平的动态变化。方法：用流式细胞仪测定1例异体肺移植患者不同时间外周血T细胞亚群细胞的百分率和CD4／CD8比值，以及用酶标ELISA法测定其不同时间外周血IL-6水平，术后监测T细胞亚群至50d，IL-6至96d，以患者术前结果作对照。结果：排异反应前CD3、CD4、CD8、NK、IL-6随着免疫抑制药应用逐渐降低，以2～4d为最低，CD4／CD8比值虽有降低，但有波动，术后第6d发生排异反应，CD3、CD4、CD8、NK迅速升高，IL-6迟于发生排异反应2d后出现高峰，予以甲强龙冲击治疗，CD3、CD4、CD8、NK并未降低到发生排异前水平，CD3、CD8、NK维持在稍低于正常的水平，CD4接近正常，CD4／CD8比值大多高于术前，IL-6也有所下降，但2个月后发生肺部霉菌等感染，IL-6也出现一个高峰。结论：外周血CD3、CD4、CD8、NK、CIN／CD8的检测，对于肺移植患者早期急性排异反应的预测有一定价值，在发生排异反应经甲强龙冲击治疗后其水平的变化与患者稳定的病情相一致，而IL-6的变化特异性不高。     

IL-6抗原抗体干预对T2DM大鼠肝脏IL-6 mRNA表达的影响

目的观察IL-6抗原及IL-6抗体对T2DM大鼠的影响,探讨IL-6等炎症因子对糖尿病发病机制的作用。方法 SD T2DM大鼠随机分为四组：糖尿病IL-6抗原组（A组）,糖尿病IL-6抗体组（B组）,糖尿病对照组（C组）,正常对照组（N组）。测定血糖、血清胰岛素、血清IL-6、肝脏胰岛素受体,RT-PCR检测肝脏IL-6mRNA表达量。结果脂肪乳灌胃（高糖高脂饮食）7周加小剂量一次尾静脉注射STZ可以成功诱导SD大鼠的T2DM模型,糖尿病组（A、B、C）较正常对照组出现明显的高胰岛素血症;IL-6抗原干预使T2DM大鼠血清及肝脏的IL-6表达增高;IL-6抗体干预可以降低其胰岛素水平。结论 IL-6作为一种致病因子能够加剧T2DM大鼠慢性低水平炎症,IL-6抗体能够改善其胰岛素抵抗状态。     

白细胞介素-6和白细胞介素-10在急性小鼠巨细胞病毒性心肌炎中的表达

目的研究IL-6和IL-10在小鼠巨细胞病毒性(MCMV)心肌炎中的表达和在心肌保护中的作用。方法60只4周龄BALB/C小鼠随机分为2组:实验组[36只小鼠,腹腔注射巨细胞病毒(MCMV)]和对照组(24只小鼠,注射3T3细胞裂解液)。应用免疫组化方法检测IL-6和IL-10在心肌组织中的表达,用病理切片观察心肌的病变。结果心肌病理结果显示,心肌组织出现灶性或弥散性炎性细胞浸润、心肌细胞的变性和坏死。心肌病理积分显示MCMV心肌炎属轻度炎症。免疫组化技术结果显示,在实验组,IL-6和IL-10蛋白主要表达在炎性浸润细胞、变性或坏死的心肌细胞,而在对照组,仅有IL-6和IL-10蛋白微量表达。结论IL-6和IL-10蛋白在MCMV心肌炎心肌组织中表达,并可能在病毒性心肌炎中起保护心肌作用。     

Modulation of the nuclear factor kappa B pathway by Shp-2 tyrosine phosphatase in mediating the induction of interleukin (IL)-6 by IL-1 or tumor necrosis factor

Shp-2, a src homology (SH)2-containing phosphotyrosine phosphatase, appears to be involved in cytoplasmic signaling downstream of a variety of cell surface receptors, although the mechanism is unclear. Here, we have determined a role of Shp-2 in the cytokine circuit for inflammatory and immune responses. Production of interleukin (IL)-6 in response to IL-1 alpha or tumor necrosis factor (TNF)-alpha was nearly abolished in homozygous mutant (Shp-2(-/)-) fibroblast cells. The targeted Shp-2 mutation has no significant effect on the activation of the three types of mitogen-activated protein (MAP) kinases, extracellular signal-regulated kinase (Erk), c-Jun NH(2)-terminal kinase (Jnk), and p38, by IL-1/TNF, indicating that Shp-2 does not work through MAP kinase pathways in mediating IL-1/TNF-induced IL-6 synthesis. In contrast, IL-1/TNF-stimulated nuclear factor (NF)-kappa B DNA binding activity and inhibitor of kappa B (I kappa B) phosphorylation was dramatically decreased in Shp-2(-/)- cells, while the expression and activity of NF-kappa B-inducing kinase (NIK), Akt, and I kappa B kinase (IKK) were not changed. Reintroduction of a wild-type Shp-2 protein into Shp-2(-/)- cells rescued NF-kappa B activation and IL-6 production in response to IL-1/TNF stimulation. Furthermore, Shp-2 tyrosine phosphatase was detected in complexes with IKK as well as with IL-1 receptor. Thus, this SH2-containing enzyme is an important cytoplasmic factor required for efficient NF-kappa B activation. These results elucidate a novel mechanism of Shp-2 in cytokine signaling by specifically modulating the NF-kappa B pathway in a MAP kinase-independent fashion.     

妇科腹腔镜手术对机体腹膜IL-6表达的影响

目的探讨妇科二氧化碳气腹腹腔镜手术对腹膜IL-6表达的影响。方法对60例子宫肌瘤或单纯卵巢囊肿患者(排除腹膜炎症)随机分别进行腹腔镜手术(30例)和开腹手术(30例),于手术0、30、60、90和120min分别采集壁层腹膜,抽提总RNA,以IL-6引物进行RT-PCR;同时取腹膜组织制成悬浮液,行ELISA法检测,检测IL-6表达情况。结果腹腔镜组IL-6在手术期间表达且有下降趋势,120min时IL-6降低,差异有显著性(与0min比较,P<0.05)。开腹组IL-6在各个时间点均有表达且持续升高,IL-6在手术60min和90min与0min比较差异有显著性(P<0.05),手术120min与0min比较,差异有非常显著性(P<0.01),120minIL-6蛋白含量较0min升高约1.7倍。腹腔镜组与开腹组同一时间点比较,IL-6蛋白含量在60min有统计学意义(P<0.05),90min和120min差异有非常显著性(P<0.01)。结论二氧化碳气腹腹腔镜组腹膜细胞因子IL-6的表达下降,开腹组增高,腹腔镜组低于开腹组,说明腹腔镜手术导致腹腔局部免疫力降低,可能在恶性肿瘤腹腔镜手术腹腔转移中起重要作用。与镜下腹腔恶性肿瘤的转移率高相符,说明黏附分子在此过程中起重要作用。     

针刺对颅脑损伤患者脑脊液IL-6及IL-8浓度的影响

目的：观察针刺治疗对重度颅脑损伤患者脑脊液中自细胞介素-6（IL-6）、白细胞介素-8（IL-8）浓度的影响及作用机制。方法：40例重度颅脑损伤患者按入院顺序随机分为对照纽和针刺组各20例,均按重度颅脑损伤常规处理。针刺组患者伤后第1灭即配合针刺人中、电针内关、涌泉、劳宫等穴。治疗1、2、3、5及7d时采用酶联免疫吸附法（ELISA）检测2组患者脑脊液中IL-6,ID8的浓度。结果：在伤后1d时2组脑脊液中IL-6,IL-8浓度与正常值比较迅速升高并达到高峰,3d开始逐步下降,7d后轻度上升。针刺组2、3、j及7d时均低于对照组（P〈0．05）。结论：针刺治疗能抑制重度颅脑损伤患者脑脊液中IL-6,IL-8的浓度,从而减轻损伤后炎症反应所致继发性脑损害。     

Insulin resistance in Graves'' disease: a quantitative in-vivo evaluation

Hyperthyroidism is considered to be an insulin-resistant state, but a quantitative evaluation of some action of insulin is still lacking. We performed euglycaemic clamp at about 350 and 7000 pmol l-1 plasma insulin concentration in combination with the 3H-glucose infusion in 12 patients with Graves' disease and in 12 matched controls. Fasting plasma insulin (126 +/- 6.5 vs. 77.5 +/- 5.7 pmol l-1; P less than 0.001), C-peptide (502 +/- 36 vs. 363 +/- 41 pmol l-1; P less than 0.001) and glucagon (47 +/- 3.3 vs. 33.3 +/- 3 pmol l-1; P less than 0.01) were significantly higher in hyperthyroids than in euthyroids. Basal hepatic glucose production was significantly higher in hyperthyroids than in euthyroids (18.3 +/- 1.4 vs. 9.2 +/- 0.5 mumol l-1; P less than 0.0001), and its suppression during physiological hyperinsulinaemia was only 50% in hyperthyroids. Glucose utilization and suppression of lipolysis were normally stimulated by insulin. All parameters altered during hyperthyroidism were normalized during methimazole-induced euthyroidism. We conclude that insulin resistance involves mainly glucose rather than lipid and is selective at the hepatic level.     

Mechanisms involved in IL-6-induced muscular mechanical hyperalgesia in mice

Interleukin-6 (IL-6) is an inflammatory cytokine known to modulate muscle pain. However, the mechanisms underlying this effect still remain unclear. Here we show that the injection of IL-6 into mice gastrocnemius muscle evoked a time- and dose-dependent mechanical hyperalgesia. This effect is in part dependent on the presence of gp130 expression in inflammatory cells in the gastrocnemius muscle as well as in DRG neurons. We also demonstrated an increased inflammatory cell recruitment and cytokines levels, namely TNF-α, IL-1β and KC. TNFR1^−/− mice or mice pre-treated with the selective CXCR2 antagonist, SB225002, with the anti-macrophage, anti-TNF-α or anti-KC antibodies or with IL-1 receptor antagonist (IL-1RA) showed decreased IL-6-mediated mechanical hyperalgesia. Furthermore, systemic pre-treatment with the classically used drugs indomethacin, celecoxib, guanetidine, morphine, thalidomide or dexamethasone, also prevented IL-6-induced muscle pain. Likewise, local pre-treatment with inhibitors of phospholipase A2 (PACOCF3), phospholipase C (U73122), protein kinase C (GF109203X), protein kinase A (KT-5720) or with phosphatidylinositol 3-kinase (AS605204) also consistently diminished IL-6-induced muscle hyperalgesia. The intramuscular injection of the selective inhibitors of p38 MAPK (SB203580), ERK (PD98059) or JNK (SP60015) also prevented IL-6-mediated muscular pain. Simultaneous flow cytometry measurements revealed that ERK, p38 MAPK and JNK were phosphorylated as early as 5 min after IL-6 injection. These findings provided new evidence indicating that IL-6 exerts a relevant role in the development and maintenance of muscular hyperalgesia. The IL-6-mediated muscular pain response involves resident cell activation, polymorphonuclear cell infiltration, cytokine production, prostanoids and sympathomimetic amines release and the activation of intracellular pathways, especially MAPKs.