Release of multiple hormones by a direct action of interleukin-1 on pituitary cells

Exposure to bacterial endotoxins has long been known to stimulate the release of anterior pituitary hormones; administration of endotoxin was at one time a common clinical test of anterior pituitary function. Endotoxin is a potent stimulus for production of the endogenous pyrogenic protein, interleukin-1 (IL-1), by macrophages and monocytes. The possibility that IL-1 has a direct effect on the secretion of hormones by rat pituitary cells in a monolayer culture was investigated. Recombinant human IL-1 beta stimulated the secretion of adrenocorticotropic hormone, luteinizing hormone, growth hormone, and thyroid-stimulating hormone. Increased hormone secretion into culture supernatants was found with IL-1 concentrations ranging from 10(-9) M to 10(-12) M. Prolactin secretion by the monolayers was inhibited by similar doses. These concentrations of IL-1 are within the range reported for IL-1 in serum, suggesting that IL-1 generated peripherally by mononuclear immune cells may act directly on anterior pituitary cells to modulate hormone secretion in vivo. Incubation of IL-1 solutions with antibody to IL-1 neutralized these actions. These pituitary effects of IL-1 suggest that this monokine may be an important regulator of the metabolic adaptations to infectious stressors.     

缬沙坦对脂多糖诱导的单核细胞白细胞介素6合成的影响

目的:通过研究缬沙坦对脂多糖(LPS)诱导的正常人外周血单核细胞合成白细胞介素6(IL-6)的影响,观察缬沙坦的抗炎作用.方法:采用密度梯度离心法分离人外周血单核细胞,应用酶联免疫吸附试验分别观察LPS刺激单核细胞产生IL-6的时间及剂量效应.结果:LPS刺激单核细胞IL-6合成呈时间依赖性和剂量依赖性,10μg·L-1LPS诱导IL-6合成开始的时间是2h,在24h达高峰,其峰值是1654±765ng·L-1.缬沙坦(10-6mol·L-1～10-3mol·L-1)不能抑制10μg·L-1LPS诱导的单核细胞IL-6合成.结论:缬沙坦并不适用于抗细胞因子治疗,缬沙坦主要不是通过抗炎效应发挥抗动脉粥样硬化作用.     

Regulation of expression of the interleukin-2 receptor on hematopoietic cells by interleukin-3

Remarkable similarities in the intracellular and genetic events occur when lymphoid and hematopoietic cells are exposed to their specific growth factors. The interleukin-2 (IL-2) receptor, whose cell-surface expression is an absolute requirement for the growth and differentiation of lymphoid cells, was detected on various nonlymphoid hematopoietic cell types in this study. Cell lines consisting either of granulocyte-macrophage precursors or mast cells, which are dependent on interleukin-3 (IL-3) for their growth, expressed high levels of the IL-2 receptor on their surface. Analysis of the binding characteristics of these receptors with 125I-labeled recombinant IL-2 revealed that only receptors with low affinity for IL-2 were present on these cells. Addition of purified recombinant IL-3 to these cell lines led to an increase in IL-2 receptor gene expression within 1 hour in isolated nuclei. This IL-3--induced increase in the number of IL-2 receptors on the cell surface is maximal within 24 hours. Addition of 10,000 units of IL-2 to these cells had no apparent effect on their growth or differentiation. The presence of the receptor with only low affinity for IL-2 on hematopoietic cells and the regulation by IL-3 suggest that this receptor is involved in some important metabolic event in hematopoiesis.     

Automated chemical synthesis of a protein growth factor for hemopoietic cells, interleukin-3

Interleukin-3 (IL-3), a protein of 140 amino acids, was chemically synthesized by means of an automated peptide synthesizer and was shown to have the biological activities attributed to native IL-3. Assays of synthetic analogues established that an amino terminal fragment has detectable IL-3 activity, but that the stable tertiary structure of the complete molecule was required for full activity. The results demonstrate that automated peptide synthesis can be applied to the study of the structure and function of proteins.     

Corticotropin-releasing factor-producing neurons in the rat activated by interleukin-1

Intraperitoneal administration of human recombinant interleukin-1 (IL-1) to rats can increase blood levels of corticosterone and adrenocorticotropic hormone (ACTH). The route by which IL-1 affects pituitary-adrenal activity is unknown. That the IL-1-induced pituitary-adrenal activation involves an increased secretion of corticotropin-releasing factor (CRF) is indicated by three lines of evidence. First, immunoneutralization of CRF markedly attenuated the IL-1-induced increase of ACTH blood levels. Second, after blockade of fast axonal transport in hypothalamic neurons by colchicine, IL-1 administration decreased the CRF immunostaining in the median eminence, indicating an enhanced release of CRF in response to IL-1. Third, IL-1 did not stimulate ACTH release from primary cultures of anterior pituitary cells. These data further support the notion of the existence of an immunoregulatory feedback circuit between the immune system and the brain.     

苜蓿黄酮对脂多糖刺激下乳成分合成相关基因表达的影响

为探索苜蓿黄酮对脂多糖(LPS)刺激下乳成分合成相关基因表达的影响,采用体外细胞培养技术,将奶牛乳腺上皮细胞分成4个组:1)基础培养基(Con);2)基础培养基中加入1μg/mL的LPS(L);3)基础培养基中加入1μg/mL的LPS和75μg/mL苜蓿黄酮(L+F);4)基础培养基中加入75μg/mL苜蓿黄酮(F)。细胞在37℃,5%CO2的培养箱中培养12h后,对其乳成分合成相关基因的表达进行测定。结果表明:1)相对于对照组,L组和L+F组的酪氨酸激酶(JAK2)表达显著降低(P0.01),信号转导子和转录激活子(STAT5)和真核起始因子4E(eIF4E)表达显著升高(P0.05)。L+F组真核细胞始动因子4E结合蛋白1(4EBP1)的表达显著高于F组(P0.01),核糖体S6蛋白激酶1(S6K1)的表达显著高于L组和对照组(P0.05)。2)F组胆固醇调节元件结合蛋白1(SREBP1)的表达显著低于L组(P0.05),过氧化物酶体增殖物激活受体γ(PPAR-γ)的表达则相反;F组脂肪酸转运蛋白1(FATP1)和脂肪酸转运蛋白4(FATP4)的表达显著低于L和L+F组(P0.01),脂肪酸结合蛋白3(FABP3)和乙酰辅酶A羧化酶(ACACA)的表达则相反;对照组硬脂酰辅酶A去饱和酶1(SCD1)的表达显著高于其他各组(P0.01)。3)L+F组葡萄糖转运蛋白1(Glut1)(P0.05)、葡萄糖转运蛋白4(Glut4)(P0.05)和葡萄糖转运蛋白8(Glut8)(P0.01)的表达显著高于对照组,F组己糖激酶2(HK2)的表达显著低于L组和L+F组(P0.05),而β-1,4-半乳糖基转移酶(β-1,4-Gal T)的表达最低。因此,在无LPS刺激下,添加苜蓿黄酮可能会抑制乳脂合成;在LPS刺激下,添加苜蓿黄酮可能会促进乳蛋白和乳糖的合成。     

FGF1对牛卵巢颗粒细胞Spry基因表达的影响

【目的】研究体外培养牛卵巢颗粒细胞中Sprouty基因(Spry)的表达,探讨成纤维细胞生长因子1(FGF1)对Spry基因表达的影响。【方法】从屠宰场收集牛卵巢,剪下直径2~5 mm的卵泡,机械破碎卵泡后收集颗粒细胞进行体外培养,在培养的第5天用FGF1和PD98059处理培养的颗粒细胞,然后用Trizol提取细胞总RNA,利用牛特异性引物进行实时定量PCR检测,用ΔΔCt方法计算Spry基因的相对表达量。【结果】牛卵巢颗粒细胞可以表达Spry基因;Spry基因的表达与FGF1呈现剂量依赖关系,Spry2和Spry4的表达量随FGF1作用时间的延长呈现出先上升后下降的变化趋势;FGF1信号通过RTK/ERK通道对Spry基因的表达产生刺激作用。【结论】在体外培养的牛卵巢颗粒细胞中,FGF1信号通过RTK/ERK通道刺激牛Spry基因表达。     

Collagen synthesis by cells synchronously replicating DNA

Replication and the performance of a differentiated function have been considered antagonistic processes. When cells in culture are partially tially synchronized with 5-fluoro-2'-deoxyuridine (FUdR), the synthesis of the specialized protein (collagen) is not reduced during chromosomal replication (S period). Collagen synthesis varies with general protein synthesis through the S period.     

Selective elimination of HIV-1-infected cells with an interleukin-2 receptor-specific cytotoxin

Infection by human immunodeficiency virus type 1 (HIV-1) is associated with cellular activation and expression of the interleukin-2 (IL-2) receptor. A genetically engineered fusion toxin, DAB486 IL-2, that contains the enzymatic site and translocation domain of diphtheria toxin and the receptor binding domain of IL-2 specifically kills cells that express high-affinity IL-2 receptors. This toxin selectively eliminated the HIV-1-infected cells from mixed cultures of infected and uninfected cells and inhibited production of viral proteins and infectious virus. Thus, cellular activation antigens present a target for early antiviral intervention.     

Histone synthesis in vitro by cytoplasmic microsomes from HeLa cells

HeLa cell microsomes incorporate labeled amino acids in vitro into acid-soluble proteins which have the same electrophoretic mobility as histones isolated from tile purified HeLa cell nuclei. The capacity to Svnthesize histones in vitro is dependent on deoxyribonucleic acid synthesis in the cells from which the microsonal fraction is prepared.     

葡聚六糖诱导后对黄瓜细胞内钙信使的影响

为明确葡聚六糖诱导黄瓜后对钙信使的影响,以黄瓜叶片为试材,测定葡聚六糖诱导后黄瓜细胞内Ca2+含量及Ca2+-ATPase活性变化,同时用免疫胶体金电镜技术观察了对钙调素(Calmodulim,CaM)分布的影响。结果表明,葡聚六糖诱导后黄瓜可溶性钙含量在12 h即达到高峰值,全钙含量在24 h达到高峰值,144 h不溶性钙达到峰值,Ca2+-ATPase活性在48 h达到最高峰。电镜下观察到在黄瓜的细胞核、叶绿体、液泡、细胞间隙、线粒体、细胞壁都有CaM分布,以叶绿体和细胞壁较多,清水对照在叶绿体和细胞壁有较少分布。葡聚六糖激活钙信使系统,可能参与光合作用,从而提高植物抗病性。     

Growth in vitro of cells from hyperplastic nodules of liver induced by 2-fluorenylacetamide or aflatoxin B1

Cell suspensions obtained from hyperplastic nodules induced in rat liver by either of the two hepatic carcinogens, 2-fluorenylacetamide or aflatoxin B(1), show growth when cultured in vitro. No growth of cells from liver adjacent to the hyperplastic nodules or from liver of control rats has been obtained so far under comparable conditions. Hepatocarcinoma cells induced by 2-fluorenylacetamide grow readily in vitro but behave differently. These findings suggest that some nonmalignant cells capable of growth in vitro arise during liver carcinogenesis prior to the appearance of unequivocal cancer. Cultures of such cells may offer new avenues for the study of liver carcinogenesis.     

Glycogen deposition in the liver induced by cortisone: dependence on enzyme synthesis

The deposition of liver glycogen in starved rats given a single dose of cortisone is inhibited by puromycin and actinomycin. The former agent interferes with induced enzyme formation in general, and the latter with the cortisone-induced rise in liver enzyme levels. The results suggest that the regulatory eJffect of cortisone on carbohydrate metabolism may be brought about -by its action on the cellular concentration of certain enzyme proteins.     

Expression of interleukin-10 activity by Epstein-Barr virus protein BCRF1

Cytokine synthesis inhibitory factor (CSIF; interleukin-10), a product of mouse TH2 T cell clones that inhibits synthesis of cytokines by mouse TH1 T cell clones, exhibits extensive sequence similarity to an uncharacterized open reading frame in the Epstein-Barr virus BCRF1. Recombinant BCRF1 protein mimics the activity of interleukin-10, suggesting that BCRF1 may have a role in the interaction of the virus with the host's immune system.     

Liver organogenesis promoted by endothelial cells prior to vascular function

The embryonic role of endothelial cells and nascent vessels in promoting organogenesis, prior to vascular function, is unclear. We find that early endothelial cells in mouse embryos surround newly specified hepatic endoderm and delimit the mesenchymal domain into which the liver bud grows. In flk-1 mutant embryos, which lack endothelial cells, hepatic specification occurs, but liver morphogenesis fails prior to mesenchyme invasion. We developed an embryo tissue explant system that permits liver bud vasculogenesis and show that in the absence of endothelial cells, or when the latter are inhibited, there is a selective defect in hepatic outgrowth. We conclude that vasculogenic endothelial cells and nascent vessels are critical for the earliest stages of organogenesis, prior to blood vessel function.     

肺血管结构重建在高盐负荷诱发肉鸡肺动脉高压综合征中的作用

为探讨高盐负荷导致内鸡肺动脉重建的发生发展过程及其与肺动脉高压的关系,将160 只7 日龄AA商品代内公仔鸡,随机分成正常对照组和试验组(饮水中含质量浓度为0.30%的NaCl 溶液),分别于处理后6周内,采用右心导管法测定肺动脉压(mPAP);采用图像分析仪测定肺小动脉面积及中膜厚度.结果显示:1)试验组肉鸡的肺动脉压显著高于对照组((2.91±0.29)～(3.62±O.39)kPa vs(2.18±0.40)～(2.41±0.39)kPa);2)处理4、5、6周时,试验组肉鸡各种管径肺小动脉管壁面积,管总面积(Aw/AT=63.40±5.79)(P<0.05)和中膜厚度占外径百分值(mMTPA=38.02±3.55)均显著高于对照组(P<0.01);3)肉鸡各种管径肺小动脉 Aw/AT mMTPA 都与平均肺动脉压(mPAP)、AHI(腹水心脏指数)极显著相关.表明高盐诱发肉鸡肺血管结构重建是其导致肺动脉高压发生发展的形态学基础.     

DNA synthesis in cartilage cells is stimulated by oscillating electric fields

External oscillating electric fields (1166 volts per centimeter, 5 hertz) enhanced the incorporation of [3H] thymidine into the DNA of chondrocytes isolated from the proliferative layer of embryonic (16 days) chick epiphysis. Verapamil or tetrodotoxin at 10(-6)M concentrations completely blocked the electric field effect. Tetracaine reduced the incorporation of [3H] thymidine in both control and electrically stimulated cells. The findings support the hypothesis that Na and Ca2 fluxes generated by the electrical perturbation trigger DNA synthesis in these cells.     

小鼠吸入氢醌对肺外组织细胞 DNA 损伤的观察

目的:观察小鼠吸入氢醌对肺外组织细胞的遗传毒性。方法:将40只健康昆明种小鼠随机分为5组,室温下采用60 L静式有机玻璃染毒柜进行呼吸道吸入不同剂量(0.0、0.5、1.0、2.0、4.0 m g/m3)的氢醌染毒2周,用单细胞凝胶电泳技术(SCGE)检测氢醌染毒后的小鼠肝、肾、脾、骨髓、胸腺和外周血淋巴细胞的DNA损伤情况,分析肺外组织DNA损伤与氢醌剂量间的关系。结果:0.5~4.0 m g/m3氢醌吸入染毒,均可诱导小鼠6种组织细胞的DNA链断裂,核DNA损伤程度与氢醌染毒剂量呈剂量-效应关系。结论:不同脏器细胞对氢醌的易感性不同,肝、肾、骨髓、外周血淋巴细胞可能是氢醌的遗传毒性靶细胞。