共查询到17条相似文献,搜索用时 93 毫秒
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褪黑素抑制雌二醇诱致的垂体PRL瘤生长与血浆PRL和过氧化脂质含量的关系 总被引:2,自引:0,他引:2
雄性大鼠皮下埋置17-β雌二醇(17-β-estradiol,E2)药泵诱发垂体催乳素PRL)瘤,并每日皮下注射褪黑素(melatonin,MLT)观察MLT对E2诱发PRL瘤生长的影响.另外,采用放免法和紫外分光光度法测定大鼠血浆PRL和过氧化脂质(peroxidativelipid,PL)浓度,观察PRL瘤重量与大鼠血浆浓度间的相关关系.实验结果显示,在对照组、0.05、0.25、0.50、1.00和2.00mgMLT组,PRL瘤重量分别为115.0±71.0、85.2±41.0、58.9±24.1、72.7±23.6、79.3±56.1、74.5±46.8mg;血浆PRL浓度分别为493.46±33.3、373.78±26.5、125.13±13.3、201.79±11.2、418.88±41.3、281.94±36.4ng/ml;血浆PL水平分别为1.21±0.23、0.89±0.32、0.92±0.27、0.64±0.24、0.41±0.14、0.43±0.21△D233/ml.相关性分析表明,PRL瘤重量与血浆PRL浓度间的相关系数为0.8738(P<0.05),与血浆PL水平间的相关系数为0.5550(P>0.05),血浆PRL浓度与血浆PL水平间的相关系数为0.2141(P>0.05).该结果提示,(1)0.25(P<0.01)、0.50(P<0.05)mgMLT能有效抑制E2诱致的PRL瘤生长和PRL分泌,所有剂量的MLT均能抑制血浆PL的形成;(2)PRL瘤重量与血浆PRL浓度间呈正相关关系,PRL瘤重量与血浆PL水平间、以及血浆PRL浓度与血浆PL水平间均无相关关系.因此,我们认为,MLT抑制E2诱致的PRL瘤生长可能与MLT抑制PRL表达性分泌有关,但与MLT抗氧化作用无关. 相似文献
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本工作旨在探讨褪黑素(melatonin,MLT)抑制17-β-雌二醇(17-β-estradiol,E2)诱发的Sprague-Dawley大鼠垂体催乳素(prolactin,PRL)瘤增生的分子机制。结果表明,每只大鼠每日定时皮下注射一定剂量的MLT(0.25、0.50mg)能显著抑制E2诱发的大鼠垂体PRL瘤的增生;偏低(0.05mg)或过高剂量(1.00、2.00mg)的MLT也抑制PRL瘤的增生,但无统计学意义。采用PCR和DNA直接测序显示,与正常垂体对照组比较,PRL瘤中PRL基因增强子出现五处突变,-1885bp位点由C突变为G,-1857~-1855由ACA替换为G,-1792~-1791插入G,-1383~-1382插入GGTGTGTG片段,-1265~-1250缺失GTGTGTGTGTGTGTGT片段。0.25mg/dMLT处理组,PRL瘤中的PRL基因增强子上述个别突变部位仍然存在(-1885由C突变为G),突变消失(-1792~-1791无插入G),大部分表现为突变减弱(-1856~-1855缺失AC,-1385~-1384缺失TG,-1250~-1253缺失GTGT)。采用荧光素酶报告基因检测PRL基因增强子活性显示,正常垂体、PRL瘤和0.25mg/dMLT处理的PRL瘤三组中,PRL基因增强子的活性分别为(13448.17±3012.74)、(161831.67±60996.01)和(10212.17±2634.71)OD单位。PRL瘤组增强子活性较正常垂体升高11倍(P<0.001),MLT处理组增强子活性较PRL瘤组降低93.69%(P<0.001)。上述三组PRL基因增强子空间结构的分析表明,PRL基因增强子DNA的曲折程度为PRL瘤组>MLT处理组>正常垂体。以上结果证实,MLT抑制大鼠垂体PRL瘤增生的重要分子机制之一可能是减弱PRL基因增强子的突变,也提示MLT可减弱PRL基因增强子的突变,从而下调PRL基因的高表达,可能与降低DNA的曲折程度有关。 相似文献
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目的研究雌激素和多巴胺激动剂对雌激素受体在大鼠垂体组织表达的作用。方法20只成年雌性Wistar大鼠,切除卵巢后,随机分2组:(1)对照组(n=5),皮下植入空白硅胶管;(2)雌激素组(n=15)皮下植入含有乙烯雌酚的硅胶管,8周后,两组各处死5只大鼠,雌激素组剩余大鼠(n=10)取出硅胶管,随机再分2组,安慰剂组(n=5)给予自来水灌胃,多巴胺组(n=5)给予溴隐亭(多巴胺激动剂)灌胃,用药4周后处死动物。放免法测定血清PRL水平,用反转录一聚合酶链反应(RT-PCR)方法检测ERs在各组垂体组织中的表达,以β-actin作为内参照,借助于计算机凝胶成像系统分析表达量。结果ERa,ERβ以及TERP在各组大鼠垂体组织均有表达,其中ERα和TERPmRNA水平在雌激素组明显高于对照组(P〈0.001),在安慰剂组和多巴胺组的表达无明显差别。结论大鼠垂体组织中存在ER的表达,雌激素对ERα和TERP的表达具有升调节作用,多巴胺不影响雌激素受体的表达。 相似文献
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实验应用雄性SD大鼠,皮下埋植内置10mg雌二醇硅胶管3个月致体催乳素瘤后,取PRL瘤细胞进行外原代培养,并应用原位杂交方法,研究不同剂量的胃泌素释放肽(gastrin-releaingpeptide,GRP)和血活性肠肽(vasoactiveintestinalpolypeptide,VIP)以及E2对 离体培养的垂体PRL瘤细胞PRL基因转录的,下,GRP,VIP分别与PRL瘤细胞孵育24h后 相似文献
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利用体外翻译系统,翻译了能与雌激素效应元件(ERE)结合的全长的人雌激素受体(hER)。制备了切除卵巢的雌性大鼠子宫核抽提物,在雌激素存在下,此核抽提物能增强hER与ERE的结合。此核抽提物在50℃保温15min后,明显减弱了增强hER-ERE结合的作用。提示了核抽提物中存在着能增强hER-ERE结合的雌激素依赖的热敏感性的辅助因子。在大肠杆菌中表达了谷胱甘肽转硫酶(GST)融合的雌激素受体的DN 相似文献
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研究证明在许多生物大分子之间的相互作用中都有水分子的参与,但水分子理否参与真核基因转录调控中反式作用因子和顺式作用元件之间的结合尚未报道。本文以雌激素受体(ER)同32bp雌激素效应元件(ERE)体外结合为模型,对结合水分子的参与进行探索性研究。在凝胶阻滞分析反应系统中加入不同浓度的渗透剂甘油、蔗糖、二甲基甲酰胺、二甲基亚砜,以调节反应系统的渗透压,随着渗透剂浓度的增大,ER-ERE的结合也随着增 相似文献
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白细胞介素2对大鼠垂体前叶细胞雌激素受体蛋白含量和基因表达的影响 总被引:6,自引:0,他引:6
采用原代无血清细胞培养技术结合免疫组织(细胞)化学和半定量反转录-PCR方法,观察白细胞介素2(IL-2)对大鼠垂体前叶雌激素受体(ER)蛋白含量和基因表达的影响,以探讨IL-2和ER在大鼠重体前叶的相互关系。结果显示:在大鼠垂体前叶细胞有IL-2受体表达。在无血清培养条件下,IL-2能增加ERα蛋白含量,促进ERα基因表达,而对ERβ的作用正好相反,rhIL-2(10μg/L)作用48h后,ER 相似文献
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雌激素受体α在大鼠垂体的表达及其调控的初步探讨 总被引:4,自引:0,他引:4
张庆红 《中国应用生理学杂志》2000,16(2):100-103
目的:观察雌激素受体α(ERα)免疫反应阳性细胞在大鼠垂体的分布,并初步探讨其空因素。方法:应用免疫组织化学和原代细胞培养方法结合图像分析。结果:①正常大鼠垂体前叶和后 有丰富的ERα阳必细胞,ERα在出生3d即有表达,一月龄大鼠已达到成年大鼠水平;②卵巢毁除大鼠ERα表达减少,补充雌激素后其表达有所增高,但仍末达到正常水平;③动情期大鼠垂体前叶ERα表达最高,动情后期逐渐减少,动情间期达最低值; 相似文献
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F. Demay S. Geffroy C. Tiffoche M. de Monti M. L. Thieulant 《Cell biology and toxicology》1996,12(4-6):317-324
Analysis of the mechanism of action of estrogen receptor shows protein and mRNA polymorphism within distinct pituitary receptor-positive cells. The lactotropes exhibit unique properties in these mechanisms that distinguish them from gonadotropes. Therefore, this cell type constitutes an especially interesting model in the male as well as in the female for estrogen receptor studies.Abbreviations PRL
prolactin
- E2
estradiol
- ER
estrogen receptor
- GnRH
gonadotropin releasing hormone
- PMSG
pugnant mare serum gonadotropin 相似文献
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Summary 1. We examined the potential effect of GnRH pulses on pituitary estrogen receptor mRNA level.2. The treatment of perifused pituitary cell aggregates with four hourly pulses of GnRH (10 nM/1 min/h) resulted in a marked increase in the steady-state level of ER mRNA (25%vs unstimulated control, n = 3).3. No changes were observed for the LH ß mRNA. Data suggest, for the first time, that a cross-talk between the GnRH and nuclear ER may occur in the gonadotrope cells. 相似文献
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电针对大鼠脑内雌激素受体蛋白及其mRNA表达的影响 总被引:23,自引:1,他引:23
本文应用放射免疫分析(RIA)、RNA点杂交和Northern blot、单克隆抗体免疫组织化学和计算机图像处理技术研究电针对切除卵巢大鼠脑内雌激素受体(ER)蛋白和mRNA表达的影响。以探讨针刺作用的分子生物学机理。结果表明,切除卵巢可导致血雌二醇(E2)水平降低,动物脑内ER蛋白和mRNA的表达增强;电针实验穴位后,去卵巢大鼠血的E2含量明显增加,脑内ER蛋白和mRNA表达受到明显抑制。正常大 相似文献
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Hua Zhang Yuanwu Liu Li Wang Zhen Li Hongwen Zhang Jihua Wu Nafis Rahman Yangdong Guo Defa Li Ning Li Ilpo Huhtaniemi Suk Ying Tsang George F. Gao Xiangdong Li 《Journal of lipid research》2013,54(2):345-357
It is important to clarify the distinct contributions of estrogen/estrogen receptor (ER) and androgen/androgen receptor (AR) signaling and their reciprocal effects on the regulation of hepatic lipid homeostasis. We studied the molecular mechanisms underlying the preventive effects of estradiol (E2), dihydrotestosterone (DHT), or E2+DHT on high-fat diet-induced nonalcoholic fatty liver disease (NAFLD) in an orchidectomized Sprague-Dawley (SD) rat model. E2 is shown to be associated with decreased fatty acid synthesis in hepatic zone 3-specific manner by increasing the phosphorylation of acetyl coenzyme-A carboxylase via an ERα-mediated pathway. DHT is shown to be associated with decreased lipid accumulation and cholesterol synthesis in a hepatic zone 1-specific manner by increasing expression of carnitine palmitotyltransferase1 and phosphorylation of 3-hydroxy-3-methyl-glutaryl-CoA reductase via an AR-mediated pathway. E2+DHT showed an additive positive effect and normalized all three impaired zones of the liver. Gene expression changes in human severe liver steatosis were similar to those of experimental rat NAFLD. Steroids reversed the histopathological NAFLD changes, likely by decreasing fatty acid and cholesterol synthesis and increasing β-oxidation. The diverse steroid effects (ER/AR) on NAFLD prevention in male rats indicate the potential applicability of ER/AR modulators for NAFLD treatment. 相似文献
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Wonwoo Lee Kyeong Ryang Ko Hyun-keun Kim Seonung Lim Sunyoung Kim 《Biochemical and biophysical research communications》2018,495(3):2242-2248
Estrogen deficiency results in an imbalance between the levels of bone-resorping osteoclasts and bone-forming osteoblasts, eventually leading to overall bone loss. Dehydrodiconiferyl alcohol (DHCA), a lignan compound originally isolated from Cucurbita moschata, has been shown to bind to estrogen receptor, and indeed exhibits various activities of estrogen, such as anti-inflammatory and anti-oxidative stress effects. In this study, we tested whether synthetic DHCA could affect the BMP-2-induced osteoblastogenesis in vitro. In MC3T3-E1 cells, DHCA promoted BMP-2-induced differentiation of osteoblasts. Consistently, the expression of three osteoblastogenic genes known to be induced by BMP-2, ALP, osteocalcin and OPG, was up-regulated by DHCA treatment. DHCA was also shown to activate the production of RUNX2 by activating Smad1/5/9 and AMPK. Data from transient transfection assays suggested that DHCA might activate the estrogen receptor signaling pathway. Effects of DHCA on BMP-2-induced osteoblastogenesis were reduced when cells were treated with a specific siRNA to ERα or ERβ. Taken together, our results suggest that DHCA may be developed as an efficient therapeutic for osteoporosis by regulating osteoblastogenesis through its estrogenic effects. 相似文献
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Masaki Iwamoto Takahiro Masuya Mari Hosose Koki Tagawa Tomoka Ishibashi Keitaro Suyama Takeru Nose Eiji Yoshihara Michael Downes Ronald M. Evans Ayami Matsushima 《The Journal of biological chemistry》2021,297(5)
Bisphenol A and its derivatives are recognized as endocrine disruptors based on their complex effects on estrogen receptor (ER) signaling. While the effects of bisphenol derivatives on ERα have been thoroughly evaluated, how these chemicals affect ERβ signaling is less well understood. Herein, we sought to identify novel ERβ ligands using a radioligand competitive binding assay to screen a chemical library of bisphenol derivatives. Many of the compounds identified showed intriguing dual activities as both ERα agonists and ERβ antagonists. Docking simulations of these compounds and ERβ suggested that they bound not only to the canonical binding site of ERβ but also to the coactivator binding site located on the surface of the receptor, suggesting that they act as coactivator-binding inhibitors (CBIs). Receptor–ligand binding experiments using WT and mutated ERβ support the presence of a second ligand-interaction position at the coactivator-binding site in ERβ, and direct binding experiments of ERβ and a coactivator peptide confirmed that these compounds act as CBIs. Our study is the first to propose that bisphenol derivatives act as CBIs, presenting critical insight for the future development of ER signaling–based drugs and their potential to function as endocrine disruptors. 相似文献