大鼠胸腺细胞糖皮质激素受体结合与糖皮质激素效应的定量关系

本文通过糖皮质激素拮抗剂 RU486阻断不同分数的糖皮质激素受体(GR)后,GR 结合与糖皮质激素(GC)效应的比较,研究于两者的量的关系。在地塞米松(Dex)10_(-9)—10_(-5)mol/L浓度范围内,Dex 和大鼠胸腺细胞 GR 的特异结合与 Dex 抑制细胞尿嘧啶核苷(Urd)参入效应呈正向平行趋势。用 RU486阻断5×10_(-8)mol/L 浓度的 Dex与 GR 结合的不同分数,比较 Dex 特异结合与抑制效应的关系,发现两者表现为线性正相关(P<0.01)。将 Dex 结合-效应直线外推,结果提示 GR 有约20%的占领阈但几乎没有备用受体。     

糖皮质激素对肥大细胞胞膜流动性的影响

目的:研究糖皮质激素(皮质酮)对肥大细胞胞膜流动性的快速作用。方法:采用荧光偏振法检测膜流动性,检测不同浓度皮质酮对肥大细胞膜流动性的快速影响以及加用糖皮质激素受体拮抗剂RU38486看其是否影响皮质酮对肥大细胞膜流动性的快速作用。结果:与阴性对照组比较,皮质酮能够在7min内剂量依赖性地快速降低肥大细胞胞膜流动性,稳定肥大细胞胞膜(P0.01);加用糖皮质激素受体拮抗剂RU38486后能部分阻断皮质酮对肥大细胞膜流动性的快速作用(P0.01)。结论:糖皮质激素能够快速降低肥大细胞胞膜流动性,稳定肥大细胞胞膜,这一作用可能是糖皮质激素快速抑制肥大细胞脱颗粒非基因组机制作用的靶点之一。     

皮质酮对大鼠下丘脑薄片室旁核神经元自发电活动的影响

本实验应用离体大鼠下丘脑薄片技术,用玻璃微电极细胞外记录、观察了下丘脑室旁核神经元的自发电活动,以及皮质酮对自发电活动的影响。在36个下丘脑薄片上观察了104个室旁核神经元的自发电活动,其放电形式主要有三种:慢而不规则(50个,占48.1%)、快速连续(44个,占42.5%)和周期性放电(10个,9.4%)。在进行皮质酮灌流的实验中,这104个单位有25个在皮质酮(10~(-7),10~(-6)mol/L)作用后,自发放电明显减少,有8个单位出现兴奋效应;其余的没有观察到明显反应。上述33个产生反应的神经元其反应特点是:潜伏期短、反应的程度与皮质酮浓度有关、糖皮质激素胞液受体阻断剂 RU38486可以阻断这种反应。结果表明糖皮质激素可以快速影响下丘脑薄片内某些室旁核神经元的电活动,为甾体激素的快速非基因机制作用提供了新的证据,提示室旁核神经元膜上有糖皮质激素受体存在。     

睾丸酮对离体培养人蜕膜细胞形态的影响

实验选用早孕人工流产蜕膜组织进行体外培养,观察睾丸酮对蜕膜细胞形态的影响并与RU 486加以比较。研究结果提示:(1)睾丸酮(6.9×10~(-5)mol/L)能抑制离体培养人蜕膜细胞的生长发育,但这种抑制作用是暂时和可恢复的且与用药剂量及持续时间有关。(2)睾丸酮对蜕膜细胞形态的影响与RU 486(4.7×10~(-4)mol/L)的作用效果相似。     

吗啡和血管紧张素Ⅱ对大鼠脑突触小体Ca~(2 )摄取的拮抗效应

行为实验已多次证明,脑室注射血管紧张素Ⅱ(AⅡ)可以对抗吗啡的镇痛作用,但机制不明。吗啡阻止神经末梢钙摄取被认为是其镇痛的机理之一,因此本工作研究了AⅡ和吗啡对大鼠脑突触小体~(45)Ca摄取的作用及相互关系。结果表明,吗啡(10~(-8)—10~(-6)mol/L)对~(45)Ca摄取有明显的抑制作用,10~(-7)mol/L时抑制41％(P<0.001),该效应可被吗啡受体阻断剂纳洛酮(10~(-6)mol/L)完全翻转。与吗啡的作用相反,AⅡ(10~(-8)—110~(-6)mol/L)可促进突触小体对~(45)Ca的摄取,10~(-7)mol/L时增加75％(P<0.001),该效应可被AⅡ受体阻断剂Saralasin(10~(-6)mol/L)完全翻转。将不同剂量的AⅡ(10~(-8)—10~(-6)mol/L)和10~(-8)mol/L吗啡与突触小体共同孵育,则吗啡抑制~(45)Ca摄取的作用被完全翻转。以上结果表明,AⅡ促进脑突触小体Ca~(2 )摄取,对抗了吗啡抑制Ca~(2 )摄取的作用,可能是AⅡ抗吗啡镇痛的机制之一。     

酪氨酸对人离体滋养层细胞孕酮与hCG分泌的影响

本文观察三种剂量(2×10~(-5)mol/L,2×10~(-4)mol/L和2×10~(-3)mol/L)的酪氮酸对离体培养的滋养层细胞孕酮及hCG分泌的影响,并对其抑制效应的机理作了初步探讨。实验结果表明,三种剂量的酪氨酸均可抑制滋养层细胞孕酮分泌(P<0.01),但是,在孕酮分泌受酪氨酸抑制的同时,未见对hCG分泌发生影响(P>0.05),进一步观察了酪氨酸对滋养层细胞3β-羟甾脱氢酶活性的影响,结果表明,酪氨酸能显著抑制3β-羟甾脱氢酶活性,提示酪氨酸对滋养层细胞孕酮生成的抑制作用与抑制3β-羟甾脱氢酶活性有关。     

阿片肽类物质对大鼠黄体细胞孕酮生成的影响

本文观察了外源性阿片肽对大鼠离体黄体细胞孕酮生成的影响,结果表明:β-内啡肽以剂量-反应依赖方式促进黄体细胞孕酮生成,有效浓度范围是10~(-8)-10~(-6) mol/L;强啡肽仅在浓度为10~(-6)mol/L时才显示刺激孕酮生成的作用;而甲硫-脑啡肽无明显作用。μ-阿片受体激动剂DAGO和乙基吗啡也能明显促进孕酮的生成。纳洛酮可完全阻断β-内啡肽,DAGO和乙基吗啡的作用。由于大鼠血液中β-内啡肽含量较低,而卵巢局部具有较高浓度的β-内啡肽。因此,我们认为,β-内啡肽可能在卵巢局部参与黄体细胞孕酮生成的调节,是卵巢内促黄体因子之一,这种作用可能是由μ-型阿片受体介导的。     

人早孕子宫蜕膜催乳素分泌的调节

子宫内膜蜕膜化对胚泡植入与妊娠维持是非常重要的。为探讨蜕膜化维持的调节机制 ,本文研究了妊娠早期人子宫蜕膜细胞催乳素 (PRL)分泌的调节。结果表明 :(1)孕酮显著地刺激PRL的分泌。 (2 )雌激素的作用与其浓度有关 ,生理浓度的雌激素对PRL分泌无明显影响 ,而高水平的雌激素抑制孕酮的刺激作用。合适的雌孕激素比例对蜕膜化的维持是必要的。 (3)RU486明显地抑制PRL的分泌 ,故认为孕酮的作用至少是部分通过受体介导的机制。 (4 )高浓度的cAMP (≥ 10 -5mol/L)显著增加PRL的分泌 ,cAMP信号系统可能在蜕膜化反应中发挥重要作用。     

辣椒素对家兔房室结细胞自发活动的电生理效应

本工作旨在研究辣椒素对家兔房室结细胞自发活动的电生理效应及其作用机制.应用经典玻璃微电极记录方法,观察到辣椒素(1～30 μmol/L)剂量依赖性地抑制房室结起搏细胞的动作电位幅度,零相最大上升速度(Vmax),舒张期除极速度和起搏放电频率,而且延长复极化90%时间(APD90).应用L型钙通道开放剂Bay K8644(0.5 μmol/L),以及提高灌流液中钙离子浓度(5 mmol/L),均可抑制辣椒素对起搏细胞的电生理效应.辣椒素受体阻断剂钌红(10μmol/L)对辣椒素(10μmol/L)的上述电生理效应并无影响.上述结果表明,辣椒素能抑制家兔房室结的自发活动,此效应可能与其抑制钙离子内流有关,但并非由辣椒素受体介导.     

皮质酮对高钾诱导PC12细胞内钙升高的非基因组调节作用

目的：分析皮质酮快速抑制高钾诱导PC12细胞内钙升高的机制。方法：使用荧光影像系统,实时检测细胞内钙变化。结果：①在预处理PC12细胞5min后,皮质酮可呈量－效关系抑制高钾诱导的PC12细胞内钙升高。②牛血清白蛋白耦联的皮质酮（B－BSA）可模拟皮质酮快速抑制高钾诱导PC12细胞内钙升高的作用,并呈现量－效关系。③糖皮质激素的细胞内受体拮抗剂RU38486对皮质酮快速抑制效应无明显拮抗作用。④蛋白合成抑制剂放线菌酮预处理细胞3h后,皮质酮对高钾诱导PC12内钙升高仍有较强抑制作用。结论：①皮质酮的作用点位于细胞膜上。②皮质酮的快速作用不直接依赖细胞内蛋白合成和不依赖细胞内糖皮质激素受体。③皮质酮对高钾诱导PC12内钙升高的快速抑制作用属非基因组作用。     

Effect of antiglucocorticoids on dexamethasone-induced inhibition of uridine incorporation and cell lysis in isolated mouse thymocytes

We have compared in isolated mouse thymocytes the action of progesterone, cortexolone, DXH (a 17-beta carboxamide derivative of dexamethasone) and RU 38486 (a new antiglucocorticoid molecule), on dexamethasone-induced inhibition of uridine incorporation and cell lysis, with the affinities of these drugs for glucocorticoid receptors. Our results show that progesterone, cortexolone and DXH which possess similar affinities for glucocorticoid receptors may exhibit variable, weak agonist and antagonist activities according to the parameter studied. RU 38486 was a potent competitor of dexamethasone and was able, when present in a 10-fold excess, to counteract almost completely the inhibitory action as well as the lytic action of 5 X 10(-8) M dexamethasone. This compound which exerts almost no agonist activity may therefore represent a useful tool to investigate the mode of action of antiglucocorticoids.     

牛血清白蛋白耦联皮质酮可以抑制精氨酸加压素的释放

本实验利用高体孵育脑薄片和放射免疫测定精氨酸加压素（ＡＶＰ）的方法,初步探讨了牛血清白蛋白耦联皮质酮（Ｂ－ＢＳＡ,不易进入细胞内）对大鼠下丘脑薄片（含室旁核和视上核）释放ＡＶＰ的影响和可能机制。结果：（１）Ｂ－ＢＳＡ（１０－７─１０－４ｍｏｌ／Ｌ）在２０ｍｉｎ内对大鼠下丘脑薄片ＡＶＰ的释放具有明显的抑制性效应,且呈剂量一效应关系;（２）ＲＵ４８６（１０－４─１０－３ｍｏｌ／Ｌ）能部分地阻断Ｂ－ＢＳＡ的抑制效应;（３）Ｂ－ＢＳＡ的抑制效应随孵育液中Ｃａ２＋浓度的升高而明显增强;（４）在有新毒素（１０－３─１０－２ｍｏｌ／Ｌ）存在的情况下,Ｂ－ＢＳＡ的抑制效应显著增强。上述结果表明糖皮质激素在未进入细胞内的情况下亦可抑制大鼠下丘脑薄片释放ＡＶＰ。此作用发生在细胞膜水平上,由非基因组机制所介导,可能是影响Ｃａ２＋跨细胞膜流动的结果。     

Interrelationship between RU38486 and the P450 activities in rat liver

Microsomal P450 monooxygenases contribute actively to the biotransformation of the antiglucocorticoid RU38486, an 11 beta-substituted nor-steroid. Pretreatment of adult rats by inducers of specific forms, belonging to different P450 subfamilies, affects the ability of liver microsomes to metabolize RU38486. Phenobarbital and pregnenolone 16 alpha-carbonitrile increase the metabolic activity of liver microsomes whereas methylcholanthrene decreases their capacity to oxidize the steroid. Thus P450 forms IIIA, IIB1,2 and IIC7 are good candidates to be involved in the degradation of this peculiar molecule. Our study has been completed by investigating whether RU38486 would influence the P450 spectrum. Whereas the treatment of rats with either a glucocorticoid (cortisol, dexamethasone) or an antiglucocorticoid (pregnenolone 16 alpha-carbonitrile) has been shown to induce the P450 activity by increasing the hepatic concentration of form IIIA, we observed a slight decrease of the P450 activity by treating the animals with RU38486. Moreover RU38486 was able to antagonize the P450 induction by the other steroids as well as it inhibits the synthesis of various liver enzymes induced by glucocorticoids (for instance tyrosine aminotransferase). These findings may be important for the therapeutic use of RU38486 since its inhibitory effect on P450 activity may be at the origin of drug interactions by modifying the endogenous hormonal status.     

A rapid,nongenomic action of glucocorticoids in rat B103 neuroblastoma cells

We report here a new example in which glucocorticoids (GCs) acted in a rapid, nongenomic way. In rat B103 neuroblastoma cells, 5-hydroxytryptamine (5-HT) was found to evoke an immediate rise in intracellular free calcium concentration ([Ca(2+)](i)). Pre-incubation of B103 cells for 5 min with corticosterone (B) or bovine serum albumin-conjugated corticosterone (B-BSA) concentration-dependently (10(-4)-10(-8) M) inhibited the peak increments in [Ca(2+)](i). Cortisol and dexamethasone had a similar effect, while deoxycorticosterone and cholesterol were ineffective. This rapid inhibitory effect of corticosterone could be mimicked by protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) and abolished completely by PKC inhibitors Ro31-8220 or GF-109203X. Neither pertussis toxin (PTX) nor nuclear GC receptor (GR) antagonist RU38486 influenced the rapid action of B. Our results suggest that GCs can modulate the 5-HT-induced Ca(2+) response in B103 cells in a membrane-initiated, nongenomic, and PKC-dependent manner.     

乙酰胆碱对大鼠体外抗体生成的影响

目的：观察不同浓度乙酰胆碱（ＡＣｈ,１０－１０～１０－５ｍｏｌ／Ｌ）对大鼠体外抗体生成的影响,并初步探讨其作用机制,从细胞水平了解乙酰胆碱与免疫功能之间的关系。方法：用体外抗体生成的检测方法,用绵羊红细胞（ＳＲＢＣ）刺激大鼠肠系膜淋巴结Ｂ细胞转化成抗体形成细胞（ＡＦＣ）,然后检测其抗体生成量。结果：①１０－１０～１０－７ｍｏｌ／ＬＡＣｈ能显著抑制体外抗体生成,其中１０－８和１０－７ｍｏｌ／ＬＡＣｈ的作用较强,而１０－６和１０－５ｍｏｌ／ＬＡＣｈ无明显的抑制作用;②Ｍ型胆碱能受体激动剂毛果芸香碱（１０－８和１０－７ｍｏｌ／Ｌ）能明显减弱体外抗体生成,而Ｎ型受体激动剂烟碱（１０－８和１０－７ｍｏｌ／Ｌ）没有显著的减弱作用,Ｍ型受体拮抗剂阿托品（１０－７和１０－６ｍｏｌ／Ｌ）可完全阻断ＡＣｈ抑制体外抗体生成的作用;③ＡＣｈ分别在Ｂ细胞用ＳＲＢＣ刺激后３～４８ｈ中的６个不同时间与淋巴细胞作用,其抗体生成仍然是减少的。结论：ＡＣｈ可非浓度依赖性地抑制大鼠的体外抗体生成;此作用可能由Ｂ细胞上的Ｍ型胆碱能受体介导;且ＡＣｈ可能主要影响Ｂ细胞转化的后期过程。     

Actions of RU 38486 on progesterone facilitation and sequential inhibition of rat estrous behavior: correlation with neural progestin receptor levels

The present study examined the actions of the antiprogestin RU 38486 on progesterone (P)-induced facilitation and sequential inhibition of estrous behavior and on brain cytosol progestin receptor (PR) levels in ovariectomized, estrogen-primed (0.5 micrograms of estradiol benzoate for 3 days) female rats. RU 38486 suppressed P-facilitated receptive and proceptive responses in a dose-dependent fashion when administered 1 hr prior to P. RU 38486 did not, however, block the sequential inhibitory effect of P. Indeed, when it was administered alone at a dose of 1 mg, animals were rendered behaviorally unresponsive to a P treatment 25 hr later. It is unclear whether RU 38486 is an agonist for P sequential inhibition of estrous behavior or if the apparent agonist action of RU 38486 actually results from a long-term antagonist effect. Estrogen-induced PRs remain elevated (35-55% above basal) in the hypothalamus (HYP) and preoptic area (POA) at 24 and 48 hr following the last estrogen injection. Thus P facilitation of estrous behavior is correlated with increased levels of cytosol PRs. RU 38486 reduced cytosol PRs in both brain regions to basal levels within 2 hr, and the levels remained suppressed 25 hr following the treatment. Hence there is a strong correlation between behavioral inhibition and suppressed cytosol PRs at both short (5 hr) and long (25 hr) intervals after RU 38486 administration. A P treatment which produced sequential inhibition of estrous responsiveness 24 hr later did not reduce the estrogen-induced level of cytosol PRs in either brain region. These results suggest that mechanisms in addition to induction of PRs may be necessary to ensure successful mating.     

内皮素—1对大鼠排卵前卵泡颗粒细胞产生孕酮的影响

本文用离体细胞体外孵育法研究了内皮素－１（ＥＴ）对大鼠排卵前卵泡颗粒细胞孕酮生成的影响及其作用机理。结果发现,ＥＴ能显著抑制ｈＣＧ刺激下的孕酮产生,抑制作用在浓度为１０－８ｍｏｌ／Ｌ时,即有显著意义（Ｐ＜０．０５,ｎ＝６）,至１０－７ｍｏｌ／Ｌ时则有非常显著的意义（Ｐ＜０．０１,ｎ＝６）;不同浓度ＥＴ（１０－７—１０－７ｍｏｌ／Ｌ）,对颗粒细胞基础孕酮的产生无明显影响。进一步研究表明,ＥＴ对ｈＣＧ刺激下孕酮生成的抑制作用,在用免抗人内皮素抗血清（ＥＴ－Ａ）１：１０００及ｃＡＭＰ后能明显被逆转。实验中还观察到,ＥＴ使颗粒细胞ＬＨ／ｈＣＧ受体数下降,亲和力降低。本文结果提示,ＥＴ可能为卵巢内的一种局部调节肽,通过作用于ＥＴ受体,干扰ＬＨ／ｈＣＧ受体功能和ｃＡＭＰ生成而抑制颗粒细胞孕酮的产生。