白黎芦醇对GH3细胞生长和泌乳素合成分泌的抑制作用及其与雌激素受体的关系

目的探讨白黎芦醇（RE）对垂体腺瘤GH3细胞增殖和泌乳素（PRL）合成分泌的影响，及其与雌激素受体（ERs）的关系。方法RE作用于GH3细胞．用免疫荧光法和Western印迹法测定ERs的表达情况．分别用ELISA法和Western印迹法测定培养基内和细胞内PRL水平，用MTT法测定细胞增殖，同时观察了雌二醇（E2）和特异性雌激素受体激动剂对RE的拮抗作用。结果RE改变ERs表达水平，减少PRL合成分泌，抑制GH3细胞增殖，E2和特异性雌激素受体激动剂对RE有拮抗作用。结论RE通过ERs抑制PRL合成、分泌及细胞增殖，从而发挥抗肿瘤作用，两种效应的信号转导途径不尽相同。     

白藜芦醇对垂体腺瘤GH3细胞增殖和PRL合成的拮抗作用

目的探讨白藜芦醇对雌激素诱发的垂体腺瘤细胞系（GH3细胞）增殖和泌乳素（PRL）合成的拮抗作用。方法在无血清无酚红的条件下，将雌二醇（E2）单独或与白藜芦醇联合作用于培养的GH3细胞，用甲基噻唑基四唑（MTT）比色分析法测定细胞生长，用免疫荧光及Western Blot检测GH3细胞增殖和PRL的表达情况。结果白藜芦醇对雌二醇诱发的细胞增殖和PRL合成均有拮抗作用，其中对PRL合成的拮抗作用较强。结论白藜芦醇对雌二醇诱发的细胞增殖和PRL合成均有拮抗作用，从而起到抗肿瘤的作用。     

白黎芦醇对垂体腺瘤GH3细胞的抑制作用

目的 探讨选择性雌激素受体调节剂白黎芦醇对垂体腺瘤GH3细胞中电压依赖性K^ 电流(IK(V))和细胞增殖的影响。方法 不同浓度白黎芦醇作用GH3细胞，应用MTT比色法测定细胞增殖，流式细胞仪检测细胞周期分布，运用全细胞膜片钳技术记录和分析白黎芦醇对GH3细胞中IK(V)的作用。结果 白黎芦醇作用GH3细胞3d后，以浓度效应关系抑制GH3细胞增殖，并使细胞增殖周期中G0／G1期阻滞，S期和G2／M期百分率降低。全细胞膜片钳结果显示，白黎芦醇以浓度和时间效应抑制IK(V)。结论 白黎芦醇抑制GH3细胞增殖可能是通过阻断电压依赖性K^ 通道起作用。提示可应用选择性抗雌激素药物治疗垂体腺瘤。     

氟维司群对泌乳素瘤GH3细胞系增殖和分泌的影响

目的探讨雌激素受体拮抗剂氟维司群对泌乳素腺瘤GH3细胞增殖和分泌泌乳素的影响。方法将GH3细胞分为对照组、不同浓度的氟维司群组（0．04、1、25、625nM）和雌二醇组。观察氟维司群和雌二醇对GH3细胞活力、泌乳素水平、凋亡以及转化生长因子-β3（Transforming growth factorβ3,TGF—β3）的影响。结果与对照组相比,雌二醇组GH3细胞活力明显增加（P〈0．01）,氟维司群25nM组和625nM组细胞活力分别下降35．3％和42．4％,差异显著（P〈0．01）。与对照组和雌二醇组相比,1nM组凋亡细胞增加,差异有统计学意义（P〈0．05）,25nM组和625nM组凋亡细胞数分别占总细胞数12．9％和17．3％．差异显著（P〈0．01）。与对照组相比,氟维司群能抑制泌乳素分泌,25nM组和625nM组分别下降62.3％和81．6％,差异佩著（P〈0．01）。蛋白印迹试验证实雌激素可抑制TGF—β3表达,随着氟维司群浓度增加,TGF-β3表达量逐渐上升。结论雌二醇可促进GH3细胞增殖和泌乳素分泌,而雌激素受体拮抗剂氟维司群能够有效抑制雌激素作用,期问有TGF—β3参与,为泌乳素瘤临床治疗提供新的药物选择。     

4-羟基他莫昔芬对泌乳素腺瘤GH3细胞增殖和分泌的影响

目的探讨雌激素受体拮抗剂4-羟基他莫昔芬（OHTam）对泌乳素腺瘤GH3细胞增殖和分泌泌乳素的影响。方法用逆转录多聚酶链反应（RT—PCR）的方法测定泌乳素腺瘤GH3细胞中雌激素受体-mRNA（ER—mRNA）的表达,并观察在去激素培养条件下以及不同浓度的OHTam和雌二醇（E2）对GH3细胞生长速度、生长抑制率、雌激素受体-mRNA（ER—mRNA）及泌乳素分泌水平的影响。结果在E2（10^-8mol／L）组细胞吸光度为0．561±0．018,抑制率为-0．06,细胞计数、生长抑制率、ER—mRNA及泌乳素分泌水平与去激素培养组差异显著（P〈0．05）;E2（10^-6mol／L）＋OHTam（10^-6mol／L）组吸光度为0．504±0．014,抑制率为0．08,细胞计数、ER—mRNA及泌乳素分泌水平与E2（10^-8mol／L）组差异显著（P〈0．05）。结论泌乳素腺瘤GH3细胞有雌激素受体表达,E2可以促进GH3细胞的增殖和泌乳素的分泌,而雌激素受体拮抗剂OHTam能够有效抑制雌激素的作用。     

罗格列酮抑制垂体腺瘤GH3细胞及促凋亡作用的研究

目的探讨罗格列酮对GH3细胞增殖的影响及其促细胞凋亡的机制。方法不同浓度罗格列酮作用GH3细胞后,流式细胞仪检测细胞周期和细胞凋亡,Elisa法分析罗格列酮对生长激素合成的影响,Western blot法分析GH3细胞Cyclin D3、bcl-2和bax的变化。结果罗格列酮作用GH3细胞48 h后,以浓度效应关系抑制GH3细胞增殖、并使细胞增殖周期中G0-G1期阻滞,S期和G2-M期百分率降低;Western blot法示罗格列酮作用GH3细胞提高了Cyclin D3和bax的表达,而bcl-2的表达降低。结论罗格列酮促GH3细胞凋亡并抑制GH分泌,可能成为垂体生长激素腺瘤病人新的治疗方法。     

17β-雌二醇对垂体腺瘤细胞增殖和电压依赖性钾电流的影响

目的　研究 17β 雌二醇 (E2 )对垂体腺瘤GH3细胞增殖和电压依赖性K+ 电流 (IK(V) )的影响 ,探讨IK(V) 与细胞增殖的关系。方法　不同浓度E2作用GH3细胞 ,应用MTT比色法测定细胞增殖 ,流式细胞仪检测细胞周期分布 ,运用全细胞膜片钳技术记录和分析E2对GH3细胞中IK(V) 的作用。结果　E2作用GH3细胞 3d后 ,0 1nmol/L、1nmol/L和 10nmol/LE2组均明显诱导细胞增殖(P <0 0 1) ,并使细胞增殖周期中G0 /G1 期细胞比例下降 ,进入S期细胞增加。E2作用GH3细胞 2 4h后 ,E2以浓度效应关系增加IK(V) 。结论　电压依赖性K+ 通道可能参与E2对GH3细胞的促增殖作用。提示可应用K+ 通道阻断性药物治疗垂体腺瘤。     

氟哌啶醇对大鼠海马CA1区γ-氨基丁酸 能抑制效应的影响

目的探讨抗精神病药对海马γ－氨基丁酸（ＧＡＢＡ）能抑制效应的作用。方法利用离体海马脑片技术，采用逆－顺向双脉冲和顺向双脉冲的刺激模式，观察氟哌啶醇（２０μｍｏｌ／Ｌ）、舒必利（１００μｍｏｌ／Ｌ）对共计３１例大鼠海马脑片ＣＡ１区ＧＡＢＡ能抑制效应的影响。结果氟哌啶醇、舒必利对锥体细胞群体峰电位无影响。氟哌啶醇增强逆－顺向双脉冲刺激诱发的双脉冲抑制，减弱顺向双脉冲刺激诱发的双脉冲易化，舒必利无此作用。结论氟哌啶醇增强海马ＣＡ１区ＧＡＢＡ能抑制效应，该作用与其拮抗多巴胺Ｄ２受体无关     

17β-雌二醇对垂体腺瘤GH3细胞增殖作用的实验研究

雌激素可能在泌乳素腺瘤的发生中起重要作用[1 ] 。本实验用不同浓度 17β-雌二醇 (E2 )作用于垂体腺瘤GH3细胞株 ,探讨E2与GH3细胞增殖的关系 ,建立E2对GH3细胞增殖活性检测平台 ,为筛选有效治疗泌乳素腺瘤的抗雌激素药物奠定基础。1　资料1 1　细胞培养[2 ] :GH3大鼠垂体腺瘤细胞株引自中国医学科学院基础所细胞中心 (由美国ATCC建株 )。E2 (Sigma)设 10 - 9～10 - 1 4mol/L 6个浓度 ,每个浓度设两个复孔 ,同时设溶媒对照孔(0 0 1%乙醇 )。在一组不同浓度的E2中同时加入 1μmol/L非选择性完全雌激素受体拮抗剂ICI182 780 (ICI…     

曲格列酮减少CyclinD1的表达抑制体外培养GH3细胞增殖的实验研究

目的 探讨过氧化物酶体增殖激活受体-γ(PPAR-γ)高亲和力配体-噻唑烷二酮类药物曲格列酮对大鼠垂体腺瘤GH3细胞系增殖的影响.并初步探讨其作用机制. 方法 不同浓度的曲格列酮作用于GH3细胞,用MTT法检测各组GH3细胞生长情况,用流式细胞技术检测各组GH3细胞周期的变化,用半定量RT-PCR方法 检测各组GH3细胞CyclinD1基因mRNA的表达.结果 曲格列酮干预GH3细胞72 h后.以浓度效应关系抑制GH3细胞增殖,并使GH3细胞明显被阻滞于G1/S检测点,CyclinD1 mRNA表达明显减少,与对照组比较差异有统计学意义(P<0.05). 结论 曲格列酮能明显抑制大鼠垂体腺瘤细胞的增殖,其分子机制可能是其与PPAR-γ结合后导致CyclinD1 mRNA表达减少,从而抑制了细胞增殖,促进肿瘤细胞死亡.     

Epidermal growth factor-activated extracellular signal-regulated kinase suppresses growth hormone expression and stimulates proliferation in MtT/ E cells

The mechanism for the inhibition of growth hormone (GH) expression by the epidermal growth factor (EGF) was examined in two clonal cell lines, MtT/E and MtT/S. The former has a negligible basal level of GH, whereas the latter has a high basal GH. The treatment of MtT/E cells with retinoic acid resulted in a significant increase in GH mRNA and subsequently GH. This stimulatory response to retinoic acid was strongly suppressed by EGF. This suppression was associated with an increase in the phosphorylation of extracellular signal-regulated kinase 1 and 2 (Erk1/2). The MEK [mitogen-activated protein kinase (MAPK) kinases that activate ERK1 and ERK2] inhibitor, PD98059, clearly inhibited the phosphorylation of Erk1/2 and restored the stimulatory effects of retinoic acid. These results suggest that the inhibitory effects of EGF on GH expression are mediated by MAPK activation in these cells. By contrast to the GH-producing clones examined previously, EGF showed a marked stimulation of proliferation of the MtT/E cells through a mechanism dependent on MAPK activation. On the other hand, the inhibitory effect of EGF on GH expression was less pronounced and the stimulation of cellular proliferation was not seen in MtT/S cells, even though it induced Erk-phosphorylation similar to that seen in MtT/E. The distinct difference in the response to EGF between these two GH cell lines appears to be attributed to differences in the function of MAPK cascade in each cell line. This may reflect the developmental stage of the cells from which MtT/E and MtT/S are derived.     

白藜芦醇通过下调CD44表达抑制胶质瘤U251细胞增殖和侵袭

目的 探讨白藜芦醇对脑胶质瘤细胞增殖和侵袭的影响及可能的分子调控机制。方法 体外培养胶质瘤U251细胞,分别用浓度为0 μmol/L、50 μmol/L、100 μmol/L、150 μmol/L白藜芦醇继续培养48 h,参考Lipofectamine2000TM说明书将pcDNA3.1/CD44（CD44过表达）、pcDNA3.1（过表达对照）等质粒转染胶质瘤U251细胞并培养24 h进行后续实验。利用CCK-8法检测细胞增殖,利用Transwell实验检测细胞侵袭;RT-PCR和免疫印迹法检测细胞CD44、CyclinD1、CDK4、MMP2和MMP9的mRNA和蛋白表达。结果 白藜芦醇明显抑制U251细胞的增殖和侵袭能力（P<0.05）,而且呈浓度依赖性（P<0.05）;所以,用150 μmol/L白藜芦醇进行CD44干预实验。白藜芦醇明显抑制U251细胞CD44、CyclinD1、CDK4、MMP2和MMP9的mRNA和蛋白表达（P<0.05）,而且呈浓度依赖性（P<0.05）。CD44过表达明显抑制白藜芦醇对胶质瘤U251细胞增殖和侵袭的抑制作用（P<0.05。结论 白藜芦醇抑制胶质瘤细胞增殖和侵袭,其机制与下调CD44的表达有关。     

Temporal relationships and IL-2 dependency of prolactin-induced lymphocyte proliferation

Recombinant preparations of human prolactin (hPRL) and interleukin 2 (hIL-2) as well as monoclonal antibodies to these growth factors were used to study the synergistic interaction of PRL and IL-2 in Nb2 rat lymphoma lactogen-dependent cells. It was shown that IL-2 stimulated Nb2 cell proliferation in lactogen-free culture medium. Experiments with short-term exposure to growth factor demonstrated that PRL was required only during the initial 12 h of incubation while IL-2 was mitogenic regardless of the time it was added. Antibody to IL-2 partially inhibited both PRL- and IL-2-induced proliferation whereas antibody to PRL significantly decreased PRL but not IL-2-induced proliferation. These findings suggest that the complete mitogenic effect of PRL on Nb2 cells requires stimulation of IL-2 production.     

Interleukin regulation of prolactin and corticotropin from pituitary adenoma

Recent findings indicate that lymphokines, leukocyte-derived hormones, interact with the hypothalamic-pituitary axis. We examined the role of neurotrophic lymphokines in the neuroendocrine system. Specifically, the action of Interleukin (IL)-1b, IL-2 and IL-6 upon the anterior pituitary hormones, growth hormone (GH), prolactin (PRL) and adrenocoticotropic hormone (ACTH) were studied in rodent pituitary adenoma cell lines. Hormone release by GH and PRL-producing rat adenoma cells (GH3) and ACTH-producing mouse adenoma cells (AtT-20) was analyzed by radioimmunoassay (RIA). Recombinant (r) IL-1beta decreased PRL release from GH3 in a dose-dependent fashion. IL-1 inhibition of PRL production occurred in parallel with IL-1 inhibition of DNA synthesis in GH3 as measured by [(3)H] thymidine incorporation. This result strongly indicates that IL-1 alters PRL production by adenoma cells at the translational level. Low dose IL-2 (10 U/ml) enhanced ACTH production from AtT-20, but higher concentrations of IL-2 failed to affect the release of ACTH. IL-2 did not change the incorporation of [(3)H] thymidine in AtT-20. Previous studies showed that IL-1 and IL-6 induce a significant secretion of ACTH via the hypothalamic-pituitary axis. However, IL-1 and IL-6 failed to affect ACTH secretion by AtT-20. Blood-derived cytokines have direct effects on hormone secretion by pituitary adenoma cells in vitro.     

Resveratrol attenuates oxidized LDL-evoked Lox-1 signaling and consequently protects against apoptotic insults to cerebrovascular endothelial cells

Cerebrovascular endothelial cells (CECs) are crucial components of the blood–brain barrier. Our previous study showed that oxidized low-density lipoprotein (oxLDL) induces apoptosis of CECs. This study was designed to further evaluate the effects of resveratrol on oxLDL-induced CEC insults and its possible molecular mechanisms. Resveratrol decreased the oxidation of LDL into oxLDL. Additionally, the oxLDL-caused oxidative stress and cell damage were attenuated by resveratrol. Exposure of CECs to oxLDL induced cell shrinkage, DNA fragmentation, and cell apoptosis, but resveratrol defended against such injuries. Application of Lox-1 small interference (si)RNA into CECs reduced the translation of this membrane receptor, and simultaneously increased resveratrol protection from oxLDL-induced cell apoptosis. By comparison, overexpression of Lox-1 attenuated resveratrol protection. Resveratrol inhibited oxLDL-induced Lox-1 mRNA and protein expressions. Both resveratrol and Lox-1 siRNA decreased oxLDL-enhanced translocation of proapoptotic Bcl-2-associated X protein (Bax) from the cytoplasm to mitochondria. Sequentially, oxLDL-induced alterations in the mitochondrial membrane potential, cytochrome c release, and activities of caspases-9, -3, and -6 were decreased by resveratrol. Pretreatment with Z-VEID-FMK (benzyloxycarbonyl-Leu-Glu-His-Asp-fluoromethyl ketone) synergistically promoted resveratrol''s protection against DNA fragmentation and cell apoptosis. Therefore, this study shows that resveratrol can protect CECs from oxLDL-induced apoptotic insults via downregulating Lox-1-mediated activation of the Bax-mitochondria–cytochrome c–caspase protease pathway.     

白藜芦醇对缺血再灌注小鼠神经干细胞增殖作用的研究

目的研究白藜芦醇对小鼠缺血再灌注后海马区神经干细胞增殖的影响,探讨其促进缺血再灌注后神经功能恢复的机制。方法 15只雄性BALB/c小鼠随机分为缺血再灌注组、白藜芦醇组及假手术组,采用大脑中动脉线栓法制作局灶性脑缺血模型,Brdu标记增殖的干细胞,免疫组化法测定增殖细胞数。结果白藜芦醇组与缺血再灌注组相比Brdu阳性细胞数存在差异。结论白藜芦醇可以促进小鼠缺血再灌注后海马区神经干细胞的增殖,可能在其促进缺血后神经功能恢复中发挥作用。