大鼠肝细胞膜高密度脂蛋白受体的研究

作者以~(125)碘标记不含apoE的人HDL_3为配体,采用简便的聚乙二醇(PEG)沉淀分离法,建立了纯化的大鼠肝细胞膜HDL受体分析法。最终浓度为12.5％的PEG能有效沉淀~(125)I-HDL_3-膜受体复合物,总结合中94％以上为特异性结合(非特异性结合在有过量25倍的非标记HDL_3存在下     

载脂蛋白AⅠ、CⅠ、CⅡ、CⅢ、E对肝细胞膜高密度脂蛋白受体结合功能的影响

以~(125)碘标记人不含apoE HDL_3为配体,研究纯化人apoAI、CⅠ、CⅡ、CⅢ、Cs及E对大鼠肝细胞膜HDL受体结合功能的影响。结果:非标记apoAI及apoCs均可有效竞争性抑制~(125)I-HDL_3与肝细胞膜HDL受体的结合;apoC亚类中,apoCⅢ抑制活性最强,抑制曲线与apoAI相似,非标记apoE则无明显抑制活性。表明apoC(尤其是apoCⅢ)对肝细胞膜HDL受体活性有重要调节作用,提示HDL受体可能是一种能识别和结合apoA及apoC的“apoA/C受体”。     

小鼠腹腔巨噬细胞HDL受体结合特性研究(简讯)

以BA-酶联法研究小鼠腹腔巨噬细胞(Mφ)HDL受体的结合特性。将Mφ培养在96孔塑料板的孔内,加入Biotin共价偶联的HDL_3(不含ApoE),保温3 h后加入Avidin-过氧化物酶复合物后,30min后,形成HDL受体-Biotin-HDL-Avidin-过氧化物酶复合物,加入底物(OPD),便可根据底物颜色的变化情况,于490 nm处比色后,定量研究HDL受体的结合特性。本法简便快速,可检测0.3 ng的结合HDL_3。 研究结果表明,HDL_3与受体结合的Kd=3.1×10~(-8) mol/L,B_(max)=167 ng/mg细胞蛋白。HDL_3中含ApoA-Ⅰ的颗粒与受体结合的Kd=6.99×10~(-8) mol/L,B_(max)=135ng/mg细胞蛋白。HDL_3中含ApoA-Ⅱ的颗粒与HDL受体结合的Kd=1.1×10~(-7)mol/L,B_(max)=50ng/mg细胞蛋白。结果提     

高甘油三酯-极低密度脂蛋白在大鼠腹腔巨噬细胞结合部位的初步探讨

从高甘油三酯(HTG)大鼠动物模型中获取纯度较高、并有生物活性的高甘油三酯-极低密度脂蛋白(HTG-VLDL)。用乳过氧化物酶法~(121)Ⅰ标记HTG-VLDL,并将此~(125)Ⅰ-HTG-VLDL与正常大鼠腹腔巨噬细胞在体外共同培养,测得~(125)I-HTG-VLDL在该细胞的吸收,降解的时间曲线、剂量曲线及竞争抑制曲线。实验结果表明:~(125)Ⅰ-HTG-VLDL与鼠腹腔巨噬细胞的结合与降解具有时间饱和性、剂量饱和性及竞争抑制现象。提示鼠腹腔巨噬细胞表面可能存在能与HTG-VLDL结合并具受体性质的结合部位。HTG-VLDL可能通过受体途径的介导进入鼠腹腔巨噬细胞中代谢。     

肝细胞膜高密度脂蛋白受体的增溶及其结合特性的研究

本研究用非离子型去污剂Triton X-100在0.125mol/L Tris-Maleate缓冲液(pH6.2)中,从粗提取的大鼠肝细胞膜上,增溶出可特异结合人不含apoEHDL_3的受体蛋白。该受体蛋白与~(125)I-HDL_3的结合为特异的可饱和过程,Scatchard作图为直线,kd为     

高密度脂蛋白(HDL)受体的研究 Ⅲ.HDL与HDL受体结合机理的初步研究(简报)

在证明北京鸭肝脏有高密度脂蛋白(HDL)受体,并对其理化性质进行研究的基础上,本研究探讨HDL受体与HDL的结合机理. 实验观察细胞表面HDL受体与周围分子的关系及其对受体-配基结合活性的影响.北京鸭肝细胞膜分别用磷脂酶A_2或链霉蛋白酶处理后,~(125)I-HDL与肝细胞膜的结合活性仅受到部分影响,但鸭肝细胞膜先用磷脂酶A_2处理再用链霉蛋白酶处理后,~(125)I-HDL与肝细胞膜的结合活性几乎消失.上述结果提示,肝细     

心钠素在大鼠肾脏和血管上的特异结合部位

用~(125)Ⅰ-心钠素放射自显影和受体分析法证明,在大鼠肾脏、血管壁和人的血管床上有心钠素的特异结合部位。这种结合可以特异地被人工合成的心钠素所竞争、取代,而不能被其他的肽所竞争、取代。放射自显影显示,这些特异结合部位主要分布在肾小球、肾脏皮、髓质交界处肾小管的上皮细胞和血管壁的平滑肌细胞。     

用酶标配体法研究低密度脂蛋白受体活性

人低密度脂蛋白用过氧化物酶标记(LDL-HRP)后,与成纤维细胞共同孵育,然后用肝素将结合在受体上的LDL-HRP洗脱下来,测定肝素洗液中LDL-HRP量和细胞数,并计算每个细胞表面的功能性受体数.结果表明,在普通培养液中,每个细胞表面平均有(7.5～8.2)×10~3个LDL受体;其活性受培养液中胆固醇浓度调节;胰岛素cGMP、可提高受体活性并促进细胞增殖;cAMP提高受体活性但抑制细胞增殖;放线菌素D抑制细胞增殖并降低受体活性.以LDL-HRP为探测剂,可对LDL受体进行超微结构形态学定位,根据酶反应产物的多少,也可以粗略地估计LDL受体活性.     

人血小板低密度脂蛋白受体的探讨

用~(125)Ⅰ标记(Iodogen法)低密度脂蛋白(~(125)Ⅰ-LDL),其比放射性为(1.94-1.0)×10~4Bq/μg,标记率为98.44±0.9％。~(125)Ⅰ-LDL与洗涤法分离的血小板结合,37°C下孵育60 min,结合达到平衡,不需二价阳离子存在。未标记的LDL可抑制~(125)Ⅰ-LDL与血小板的结合,而纤维蛋白原,白蛋白等无此作用。每个血小板约可结合3504±735个LDL分子,具有饱和性,解离常数Kd值为(4 5±2.1)×10~(-9) mol/L。高密度脂蛋白能抑制结合。结果提示血小板有LDL特异性受体,LDL有可能通过受体介导影响血小板功能。     

大鼠肝实质及非实质细胞VLDL和HDL受体的研究

作者以~(125)I-标记的人VLDL和不含apo E的HDL_3为配体,研究了大鼠肝实质细胞(PC)及非肝实质细胞(NPC)的VLDL和HDL受体的生物学特性。结果显示:VLDL受体和HDL受体均可介导肝PC和NPC结合、摄取及降解相应的脂蛋白;肝NPC上该二受体的活性分别为PC的10倍和4倍;肝NPC上VLDL受体HDL受体的解离常数分别为15.0～34.2μg/ml和10.1～17.7μg/ml,最大结合容量分别为2170～2607ng/mg和1004～2738ng/mg细胞蛋白;VLDL受体活性受EDTA抑制及胆固醇的下降调节,HDL受体不受EDTA抑制但受胆固醇的上升调节。发现apoCⅢ对VLDL受体结合功能有明显抑制作用。     

CHARACTERIZATION OF HDL BINDING SITES AND ITS LIGAND IN CULTURED SMOOTH MUSCLE CELLS OF RABBIT''S AORTA

Cultured smooth muscle cells of rabbit aorta were studied by 125I labelled rabbit HDL3. Saturation curves, measured at 4 C, showed the presence of two different components: the low-affinity non-saturable binding portion and the high-affinity binding portion (Kd about 5.6 x 10(-8) mol/L and Bmax about 0.321 micrograms/mg cell protein). Scatchard analyses of the high-affinity binding portion suggest the presence of single class binding sites. Binding of rabbit HDL3 to cultured smooth muscle cells was relatively resistant to trypsin or pronase, and independent to Ca2+. The binding rate of 125I-HDL3 to the smooth muscle cells was highest at 4 C and the optimal pH was 2. Additionally, presence of high concentration apoAI reduced 50% of the binding rate of 125I-HDL3, and 125I-HDL3, being pretreated (blocked) with rat anti-rabbit apoAI IgG of different concentrations lost 70% of its original binding rate with smooth muscle cells. The results suggest that rabbit aorta smooth muscle cells possess a specific binding sites for apoE-free HDL which recognizes apoAI as a ligand.     

大鼠肝非实质细胞载脂蛋白CⅢ结合位点（受...

Binding sites of apolipoprotein (apo) C III on non-parenchymal cells (NPC) isolated from rat liver were found. Apo C III was purified from delipided human plasma very low density lipoproteins. 125I-labeled-apo C III was prepared by chloramine-T method. Non-parenchymal cells were isolated from rat liver by collagenase method. Freshly isolated rat liver NPC bound 125I-labeled apo C III in a saturable way with Kd 0.1-0.55 mumol/L and Bmax 18.1-42.0 ng/ml cell protein. There were about 1.0-4.5 x 10(5) specific binding sites of apo C III on each NPC. Unlabeled apo C III, but not apo AI and B100, could inhibit these binding activities. The results demonstrate the presence of saturable and specific apo C III receptors (binding sites) on rat liver NPC, but their nature and biologic properties remain to be investigated.     

载脂蛋白AⅠ,CⅠ,CⅡ,CⅢ,E对肝细胞膜高密度脂蛋白...

Effects of purified human apolipoproteins AI, CI, CII, CIII-1, Cs and E on the binding of 125I-labeled apo E-deficient HDL3 to isolated rat liver plasma membranes were investigated. Unlabeled apo AI, CI, CII, CIII-1 and apo Cs, but not apo E, could effectively inhibit 125I-labeled HDL3 binding to liver membranes, apoCIII-1, was the strongest among the apoC subclasses and the inhibition curve of apoCIII-1 was similar to that of apo AI. This result indicates that apo C, especially apo CIII, may be another specific ligand of HDL receptor, and it plays an important role in regulation of HDL receptor activity in liver.     

Suppression of induced atherosclerosis in h-apo AI transgenic mice by overex pression of human apo AI in the aortic wall

ｅｔｈｏｄｓ　Ｂｏｔｈｈ ａｐｏＡＩｔｒａｎｓｇｅｎｉｃｍｉｃｅａｎｄｎｏｒｍａｌＣ57ｍｉｃｅｗｅｒｅｆｅｄｗｉｔｈｅｉｔｈｅｒａｒｅｇｕｌａｒｃｈｏｗｏｒａｈｉｇｈ ｆａｔｄｉｅｔｃｏｎｔａｉｎｉｎｇ 5%ｐｏｒｋｌａｒｄ ,1 2 5%ｃｈｏｌｅｓｔｅｒｏｌａｎｄ 0 2 5%ｓｏｄｉｕｍｃｈｏｌａｔｅｆｏｒ 14ｏｒ 2 4ｗｅｅｋｓｒｅｓｐｅｃｔｉｖｅｌｙ ＨｕｍａｎａｐｏＡＩｍＲＮＡｗｅｒｅｄｅｔｅｃｔｅｄｂｙＮｏｒｔｈｅｒｎｂｌｏｔ ＰｌａｓｍａａｐｏＡＩｌｅｖｅｌｓｗｅｒｅｍｅａｓｕｒｅｄｕｓｉｎｇａｒａｄｉ…     

UROTENSIN II RECEPTOR IN THE RAT AIRWAY SMOOTH MUSCLE AND ITS EFFECT ON THE RAT AIRWAY SMOOTH MUSCLE CELLS PROLIFERATION

INTRODUCTIONUrotensinII（U－II）isavasoactive“somatostatin－like”cyclicpeptidewhichwasoriginallyisolatedfromfishspinalcordsandwhichhasrecentlybeenclonedfromman（１,２）．Ames,etal．recently（in１９９９）identifiedanorphanhumanG－protein－coupledreceptorthatishomol－ogoustoratGPR１４andexpressedpredominantlyincar－diovasculartissue,whichfunctionsasaU－IIreceptor．HumanU－IIisfoundwithinbothvascularandcardiactissue,includingcoronaryatheroma．ThepotencyofvasoconstrictionofU－IIi…     

HDL and apolipoprotein A1 (apo A1). Their effects on retardation of lipid deposition in aortic intima.

The aim of this study is to clarify whether apo A1 displays a similar role as that of HDL in preventing the development of experimental atherosclerosis. Results were obtained from 4 groups of experiments. (1) Result from 4 successive experiments of tree shrews indicated that high serum HDL level is the main factor in preventing the development of experimental atherosclerosis; (2) Results from 4 successive experiments in rabbits showed that both HDL and apo A1 were able to decrease the extent of lipid deposition and atheromatous lesion developed in the aortic intima; (3) Apo A1 also inhibited the number of monocytes/macrophages infiltrated in aortic intima at the initial stage of fatty streak formation; (4) Similar as HDL, apo A1 phospholipid liposomes promoted markedly the clearance ability of smooth muscle cells on intracellular cholesterol. Conclusively, apo A1 is effective in preventing the development of experimental atherosclerosis. Further study, however, is required to detect an ideal combination of apo A1 with other component, e.g., phospholipid.

     

内皮素-1受体在兔不全梗阻性膀胱中的研究

目的 :研究内皮素 1受体 (ET 1R)在兔不全梗阻性膀胱中的变化和意义。　方法 :采用受体的放射配基结合分析技术 (RBA) ,对 10只成年雄性新西兰白兔不全梗阻性膀胱 (兔不全梗阻性膀胱模型 ,梗阻 6周为实验组 )及 10只同龄雄性新西兰白兔无梗阻性膀胱术后 6周 (对照组 )的膀胱体及膀胱颈部平滑肌组织ET 1R进行研究。结果 :在膀胱体平滑肌组织中ET 1R结合量 ,实验组较对照组明显增多 (P <0 .0 2 ) ,而膀胱颈平滑肌组织中ET 1R结合量无明显变化 (P >0 .2 )。实验组较对照组的膀胱重量明显增加 (P <0 .0 0 1)。　结论 :兔不全梗阻性膀胱的膀胱体平滑肌组织中ET 1R结合量明显增多。ET 1具有收缩平滑肌和促平滑肌、纤维结缔组织增生 (有丝分裂 )的作用 ,故ET 1R的上调是导致兔不全梗阻性膀胱壁结构改变及功能紊乱的重要因素之一。     

人血浆HDL对高脂饲养家兔肝细胞膜HDL受体活性的影响

为进一步探讨ＨＤＬ对抗动脉粥样硬化的作用机理,采用高胆固醇膳食饲养家兔,通过静脉注射人血浆ＨＤＬ制剂,观察ＨＤＬ对高脂饲养家兔血脂、肝脏和胆囊胆汁脂质含量以及肝细胞膜ＨＤＬ受体活性的影响。结果发现：ＨＤＬ制剂虽无降低高脂饲养家兔血清脂质的作用,但可减少其肝脏脂质沉积,并且具有促进脂质经胆道排泄的作用。高脂饲养家兔的肝细胞膜ＨＤＬ受体具有Ｋｄ 值减小,Ｂｍ ａｘ 值增加的趋势;注射ＨＤＬ制剂的家兔,与正常对照比较,其Ｋｄ 值虽无明显变化,但Ｂｍ ａｘ 值显著增加（Ｐ＜ ０．０５）,表明注射人血浆ＨＤＬ可使高脂饲养家兔肝细胞膜ＨＤＬ受体呈现以受体数目增加为特征的活性升高。     

4-羟基他莫昔芬对体外培养前列腺平滑肌细胞的作用

目的 研究4-羟基他莫昔芬(OHT)对原代培养的前列腺平滑肌细胞增殖与凋亡以及雌、雄激素受体表达的影响.方法 以不同浓度的雌二醇(E2)、乙烯雌酚(DES)和OHT分别作用于原代培养的前列腺平滑肌细胞,采用流式细胞术检测增殖和凋亡,免疫细胞化学检测雌、雄激素受体表达.结果 DES和E2在一定浓度范围内起促增殖作用(均P<0.05),但未发现明显的浓度相关性(DES:r=-0.101,P=0.328;E2:r=-0.115,P=0.188).OHT浓度在1×10-8moL/L时,前列腺平滑肌细胞增殖率为5.04%±0.65%,随着浓度由1×10-6mol/L升高为1×10-5mol/L,细胞增殖率由2 79%±0 54%下降为0.93%±0.40%.在更高浓度下显示与浓度相关的促凋亡作用(5.83%±0.78%、13.70%±0.71%、19.53%±0.90%),以上作用不能被相同甚至更高浓度的E2所逆转.OHT对雌、雄激素受体表达的影响与雌激素相近.结论 OHT在一定浓度范围内对原代培养的前列腺平滑肌细胞具有明显的抑制增殖和促凋亡作用,且该作用可能不依赖于雌激素受体途径.口服他莫昔芬后OHT血药浓度较低和OHT上调雄激素受体表达可能是他莫昔芬治疗前列腺增生效果不佳的原因.     

当归挥发油对兔离体胸主动脉平滑肌的影响

目的 观察当归挥发油对兔离体胸主动脉平滑肌的作用,并探讨其作用机制.方法 制作兔离体胸主动脉平滑肌螺旋条,采用BL - 420F生物信号采集系统观察当归挥发油对正常胸主动脉平滑肌及对去甲肾上腺素(NE)和氯化钾(KCI)预收缩的胸主动脉平滑肌张力的影响.结果 当归挥发油对兔离体正常胸主动脉平滑肌具有显著的舒张作用,对...