着床前的小鼠胚胎具有生长激素及其受体功能表达:生长激素在早期胚胎中的作用

长期以来,人们一直认为胚胎和胎儿的生长并不依赖垂体生长激素(GH),然而这个观点正受到越来越多的挑战。已经证实生长激素受体(GHR)在12 d的大鼠胚胎和胎盘。51 d的绵羊胚胎以及小鼠胎盘中表达,最近Ohlsson等证明在小鼠胚胎干细胞上存在GHR及免疫反应,在小鼠囊胚上也有GHR     

重组人生长激素促进肝癌血管新生的体外研究

目的: 观察重组人生长激素(rhGH)通过不同生长激素受体(GHR)表达的肝癌细胞株,对共培养的人脐静脉内皮细胞(ECV)增殖的影响. 方法:用免疫细胞化学方法筛选GHR阳性和阴性的细胞株,分别与ECV共培养.以不同浓度的rhGH(50和250 ng/mL、空白对照)进行干预.用流式细胞仪检测细胞周期比例,ELISA法测定肝癌细胞分泌的血管内皮生长因子(VEGF)的浓度,描绘细胞生长曲线. 结果:Bel-7402(GHR阳性)在rhGH干预后分泌VEGF水平提高,与之共培养的ECV生长加速,细胞S期比例显著升高,呈现rhGH浓度依赖性(P<0.05).而SMMC-7721(GHR阴性)虽能促进ECV增殖,但不受rhGH影响,分泌的VEGF无变化(P>0.05). 结论:rhGH可诱导GHR( )肝癌细胞分泌VEGF,间接促进血管内皮细胞增殖.     

生长激素受体在结直肠癌发生过程中表达上调

目的:研究生长激素受体(GHR)在结直肠正常黏膜-非肿瘤性息肉-腺瘤-结直肠癌序列中的表达,以探讨其在结直肠癌发生发展中的作用. 方法:应用免疫组化(IHC)和逆转录聚合酶链反应(RT-PCR)检测正常结直肠黏膜、非肿瘤性息肉、结直肠腺瘤、结直肠癌共124例病人的标本中GHR表达. 结果:免疫组化结果表明,与正常结直肠黏膜相比,结直肠腺瘤和结直肠癌的GHR蛋白表达显著上调(P＜0.001);半定量RT-PCR结果同样表明,与正常结直肠黏膜相比,结直肠腺瘤和结直肠癌的GHR mRNA表达也显著上调(P＜0.001). 结论:GH/GHR在结直肠癌的发生发展过程中可能起着重要的作用,对结直肠癌病人应谨慎使用重组人生长激素.     

生长激素受体在胃癌组织中的表达及其临床意义

目的:研究人胃癌组织生长激素受体( GHR)的表达情况及其与肿瘤临床病理特点的关系. 方法:回顾性分析100例胃癌病人资料,采用免疫组化法检测组织的GHR表达,分析其与肿瘤分化程度、病理分期、Borrmann分型的关系.同时检测其中14例癌旁正常胃黏膜组织的GHR表达情况,分析正常胃黏膜与肿瘤组织GHR表达的差异. 结果:胃癌组织中GHR表达阳性率为55％ (55/100),正常组织为85.7％ (12/14).GHR表达与临床分期、组织分化程度显著相关(P＜0.01),与Borrmann分型相关(P＜0.05).GHR表达与肿瘤发生部位、性别和年龄均无相关性. 结论:胃癌组织中GHR的表达存在差异.     

重组人生长激素体外激活人结肠癌细胞JAK2-STAT3通路

目的探讨重组人生长激素（rhGH）对不同生长激素受体（GHR）表达状态的人结肠癌细胞生长及JAK2-STAT3通路的影响。方法采用流式细胞术根据GHR表达状态不同筛选结肠癌细胞株,选择LOVO细胞株和HCT-8细胞株进入实验,采用MTT法分析rhGH对人结肠癌细胞生长的作用,采用流式细胞术进行细胞增殖指数（PI）、细胞周期分析及凋亡检测,采用蛋白质印迹法分析JAK2-STAT3通路相关分子的蛋白水平变化。结果HCT-8细胞株GHR呈阳性表达（59．6％）,LOVO细胞株GHR呈阴性表达（3．5％）。rhGH显著促进HCT-8细胞生长,G2／M期比例明显高于未处理组（P=0．0073）,PI升高,凋亡率降低,且pJAK2、pSTAT3、VEGF、CyelinD1、Bcl-xL蛋白表达增加。经rhGH处理后,LOVO细胞的上述各项检测指标未出现明显变化。结论rhGH促进GHR表达较高的HCT-8细胞生长,上调JAK2-STAT3信号转导通路多个关键节点的基因表达;不促进GHR低表达的LOVO细胞生长及JAK2-STAT3通路因子表达变化。     

生长激素联合氟尿嘧啶对生长激素受体不同表达胃癌细胞株的影响

目的: 研究重组人生长激素(rhGH)联合氟尿嘧啶(5-FU)在体外对生长激素受体(GHR) 不同表达状态人胃癌细胞株的影响. 方法: 选用GHR高表达的SGC-7901和GHR低表达的MKN-45胃癌细胞株.每种细胞株分为空白对照组、5-FU处理组、rhGH处理组和联合处理组.采用四基偶氮唑蓝(MTT)比色法和流式细胞术,分析不同浓度rhGH及其与5-FU合用,对人胃癌细胞株的生长抑制、凋亡、细胞周期和增殖指数(PI)等的影响. 结果: SGC-7901细胞株:与空白对照组比,各浓度rhGH组的生长率、G2/M期比例和PI显著升高,细胞凋亡率显著降低(P<0.05);与5-FU处理组比, 各浓度rhGH+5-FU组的G2/M期比例和PI显著升高,抑制率和细胞凋亡率显著降低(P<0.05).MKN-45细胞株:不同浓度rhGH对该细胞株的分裂增殖无明显影响(P>0.05).联合处理组与5-FU处理组间的细胞抑制率、凋亡率和PI也无显著性差异(P>0.05). 结论: rhGH在体外能促进高表达GHR的胃癌细胞增殖,减弱5-FU的抗癌作用,但对低表达GHR的胃癌细胞无明显影响,也不能明显干扰5-FU的抗癌作用.     

多重探针连接依赖式扩增技术检测矮小儿童生长激素受体基因分析

目的:探讨矮小儿童生长激素受体(GHR)基因的变异情况。方法:选择矮小儿童96例,其中生长激素缺乏症(GHD)67例、特发性矮小(ISS)29例,另选择生长发育正常儿童23例,采集外周血,应用多重探针连接依赖式扩增(MLPA)技术检测GHR基因10个外显子,并分析比较GHR外显子的基因型及等位基因频率分布情况。结果:GHR基因外显子1~10均未发现信号升高,外显子1、2和4~10也未发现信号降低或缺失等异常情况;GHR外显子3信号降低和缺失的发生率在GHD组分别为34.3%、1.5%,在ISS组为17.2%、3.4%,在正常对照组为26.1%、8.7%;3组儿童GHR外显子3的3种基因型及等位基因频率的差异均具有统计学意义。结论 GHR基因外显子3在矮小及正常儿童中均存在多态性,GHR基因对身高的影响及其生物学功能有待进一步探讨。     

腹腔感染时SOCS-3和GHR mRNA表达的变化与生长激素拮抗

腹腔感染时存在生长激素拮抗 ,通过测定此时 SOCS- 3(Suppressor of Cytoline Signaling 3) ,GHR(Growth Hor-mone Receptor)和 IGF- 1(Insulin- like growth factor I) m R-NA表达的变化 ,探讨重症状态下生长激素拮抗发生的机制。采用 RT- PCR方法测定对照组及腹腔感染组大鼠肝组织SOCS- 3、GHR及 IGF- 1m RNA的表达 ;应用放射免疫法测定两组血浆中生长激素 (GH)的浓度。结果表明腹腔感染组血浆中 GH的浓度较正常组明显升高 ,分别为 0 .843± 0 .17ng/ m l和 0 .6 14± 0 .138ng/ m l,具有显著性差异 (P<0 .0 5 ) ;腹腔…     

重组人生长激素对人结直肠癌细胞株放疗敏感性的影响

目的:观察重组人生长激素(rhGH) 是否会降低结直肠癌细胞株对放疗的敏感性,并探讨其与细胞凋亡以及DNA损伤修复的关系.方法:选择生长激素受体(GHR)阳性表达的HCT-8和阴性表达的LOVO细胞,各分为单纯放疗组、rhGH 放疗组、生长激素受体中和性抗体(GHRA) rhGH 放疗组.放疗剂量分别为2 Gy、4 Gy和8 Gy;rhGH浓度为100 ng/mL;GHRA浓度为0.2 μg/mL.应用克隆形成试验评估放疗敏感性,用流式细胞仪检测细胞凋亡,应用彗星电泳法检测细胞DNA损伤.结果:经过rhGH干预的HCT-8细胞放疗后,其克隆形成率较单纯放疗组显著提高,在8 Gy放疗下尤为明显(52.1±2.9)% vs (21.0±2.7)%,P＜0.001.经GHRA预处理封闭GHR之后,这种作用消失.rhGH干预并不改变LOVO细胞接受放疗后的克隆形成率.rhGH干预显著减少了由放疗引起的HCT-8结直肠癌细胞的凋亡(2 Gy,P=0.042;4 Gy,P=0.013;8 Gy,P＜0.001 );经过中和性抗体预处理封闭GHR之后,这种作用消失.与空白对照相比,rhGH的干预使HCT-8细胞DNA初始受损的程度显著下降(Olive尾时刻21.53±2.88 vs 36.56±3.93,P=0.003),并在到达平台期后,其所处的水平与单纯放疗相比也明显下降(5.5±0.42 vs 9.07±0.84,P=0.012);在使用GHRA预处理封闭细胞表面GHR后,再加入rhGH,这种作用则消失.结论:rhGH降低GHR( )的HCT-8细胞对放疗的敏感性,GH与GHR结合,显著增强了GHR( )结直肠癌细胞对放疗诱导的DNA损伤的修复能力.     

重组人生长激素联合氟尿嘧啶体外干预人结肠癌细胞株增殖

目的:在体外环境下观察基因重组人生长激素(rhGH)及联合氟尿嘧啶(5-FU)干预不同细胞膜生长激素受体(GHR)表达水平对人结肠癌细胞的增殖情况。方法:采用免疫细胞化学法检测人结肠癌细胞株HCT-8和LOVO膜表面的GHR表达水平。每株细胞分为对照组、rhGH组、5-FU组和rhGH+5-FU组,用四甲基偶氮唑蓝(MTT)、克隆形成实验和免疫细胞化学等方法,测定各组各株肿瘤细胞的抑制率、增殖细胞核抗原(PCNA)表达变化。结果:HCT-8高表达GHR(阳性表达细胞数≥50%),LOVO未表达GHR。rhGH显著提高HCT-8细胞增殖和克隆形成率,PCNA表达增加,且联合化疗后,较LOVO组肿瘤抑制率减少(P0.05)。结论:在体外环境下,rhGH促GHR阳性表达的结肠癌细胞增殖,且对5-FU化疗有抵抗,对于不表达GHR的结肠癌细胞无上述作用。     

Hormone resistance and its modulation in breast cancer

Acquired hormone resistance is a reversible adaptative change of hormone-sensitive breast tumors promoting survival by changes in the balance and communication between estrogen receptor and growth factor signaling. The mechanisms of hormone resistance induced by various hormone therapies are different, however, their common feature is the dominance of growth factor signaling with the consequences of enhanced proliferation and decreased apoptosis. In case of tamoxifen or selective estrogen receptor modulator resistance, the agents' enhanced agonistic activity occurs. The increased expression of certain estrogen receptor coactivators may play an important role. The essential of hormone resistance after estrogen deprivation is estrogen hypersensitivity, which is a consequence of the enhanced activity of the membrane-associated estrogen receptor and its influence on the growth factor signaling. The integration of cell surface growth factor receptor or growth factor signal transduction blocking agents like tyrosine kinase, MAPK, mTOR, PI3K or farnesyl transferase inhibitors into hormone therapies may prevent or treat hormone resistance. The other possibility is to use the hormone therapies sequentially. A new promising agent is the pure antiestrogen fulvestrant which targets the estrogen receptor located in both the membrane or the nucleus. Also, estrogen therapy may revert hormone resistance. The use of predictive markers may promote treatment choice and indicate application of targeted therapies.     

Ghrelin--a hormone with multiple functions

The growth hormone secretagogue ghrelin is in the centre of interest since its discovery in 1999. It stimulates growth hormone, corticotropic hormone and prolactin secretion, but also plays an important role in the regulation of appetite, carbohydrate- and lipid metabolism and possibly on gastric acid secretion, gastric motility, heart function and as well as immune functions and cell proliferation. Ghrelin was originally identified from the stomach but it is also present in all tissue among others in: hypothalamus, pituitary, pancreas, lung, immune cells, placenta, ovary, testis, kidney and in different tumours including pituitary adenoma, neuroendocrine tumours, thyroid carcinomas, endocrine tumours of the pancreas and lung. The gene structure and its receptor are similar to motilin, they are both synthesized in the upper gastrointestinal tract and both have prokinetic activity on gut motility. The ghrelin receptor (growth hormone secretagogue receptor) is a member of G protein-coupled seven transmembrane domain receptor. The receptor is localised in the central nervous system, kidney, thyroid, pancreas, myocardium and spleen. Starvation and low body mass index decrease, while food intake, hyperglycaemia, elevated insulin levels and high body mass index increase the endogenous ghrelin levels. Although we know much about the ghrelin, number of questions remain unanswered, such as the effects of the locally-produced ghrelin or its role in the cell metabolism.     

Growth hormone receptor antagonists: potential indications

Pegvisomant is a mutated human growth hormone molecule, which binds to the growth hormone receptor. This binding, however, does not lead to signal transduction. Therefore, in high concentrations pegvisomant acts as a growth hormone receptor antagonist. In a short term study (3 months) pegvisomant was shown to be an effective treatment for acromegaly. On theoretical grounds decreasing the biological effects of growth hormone in patients with diabetes mellitus could have a favourable impact on the severity of the secondary complications associated with this disease. Animal models for diabetic retino- and nephropathy are in accordance with this concept. Human data are lacking but clinical studies investigating the effect of pegvisomant in diabetes mellitus are in preparation. Growth hormone, either directly or via its downstream effector insulin-like growth factor-I (IGF-I) has been implicated as an important factor in the growth of malignant tumours. Animal studies in which human colon and breast cancer models were used showed that pegvisomant can powerfully decrease tumour growth. Studies in cancer patients have not yet started.     

Growth hormone deficiency: an unusual presentation of floating harbor syndrome

Floating-Harbor Syndrome (FHS) is a very rare condition of unknown etiology characterized by short stature, delayed bone age, characteristic facial features, delayed language skills and usually normal motor development. This syndrome has only once been associated with growth hormone deficiency and precocious puberty in the same patient. We describe a 5 4/12 year-old girl with the typical features of FHS in whom growth hormone deficiency was diagnosed and two years later central precocious puberty was noted. The patient showed a good response to human recombinant growth hormone as well as gonadotropin releasing hormone analogue treatment.     

Growth hormone receptor antagonist in the treatment of acromegaly

Exploration of construction, function and interaction of human growth hormone and growth hormone receptor in details resulted in the innovation of the new growth hormone receptor antagonist, pegvisomant. Pegvisomant with different mechanism of action extended the tools of medical management of acromegaly. Importance of the novel treatment modality is high. In one hand the necessity of the strict control of growth hormone/insulin-like growth factor-I axis has been proven regarding the mortality of the disease. On the other hand, despite the use of all current modes of treatment (surgery, radiotherapy, dopamine agonists, somatostatin analogs), a significant cohort of patients with acromegaly remains inadequately controlled. Pegvisomant has been registered in 2004. Since 2006, it has been used in Hungary for the treatment of acromegaly in patients who have had an inadequate response to surgery and/or radiation therapy and/or other medical therapies, or for whom these therapies are not appropriate. Clinical use of pegvisomant in the treatment of acromegaly is effective, well tolerated, and safe, based on international Acrostudy database. In order to improve the efficacy of therapy clinical trials started with pegvisomant and somatostatin analog combination treatment. Evidence of several further effects of the growth hormone/insulin-like growth factor-I axis suggests other potential uses of growth hormone receptor antagonists.     

脑肠肽ghrelin在胃肠功能中的研究进展

脑肠肽激素ghrelin是一种引起生长激素释放的多肽,是迄今发现的唯一生长激素释放激素受体(GHSR)的内源性配体。循环中的生长激素释放肽主要由胃黏膜产生。Ghrelin可促进胃肠运动、调节能量代谢和影响心血管功能等。有很多研究发现,ghrelin与胃肠功能关系密切,以下就这些方面研究进展作一综述。     

Focus on the short- and long-term effects of ghrelin on energy homeostasis

The endogenous ligand for the growth hormone secretagogue receptor, ghrelin, is a 28–amino-acid peptide acylated with an octanoyl group at the serine in position 3. Most of the circulating ghrelin results from its synthesis and secretion by the X/A-like endocrine cells from the stomach and proximal small intestine. Besides its potent growth hormone secretory action, ghrelin is a highly pleiotropic hormone, contributing significantly to the regulation of appetite and food intake control, gastrointestinal motility, gastric acid secretion, endocrine and exocrine pancreatic secretions, cell proliferation, glucose and lipid metabolism, and cardiovascular and immunologic processes. The purpose of this review is to consider the orexigenic effects of ghrelin on short-term regulation of food intake and long-term regulation of body weight, the implications of genetic ghrelin and growth hormone secretagogue receptor polymorphism, and the use of antagonists and agonists of ghrelin in pathophysiological conditions.     

Chelation of zinc amplifies induction of growth hormone mRNA levels in cultured rat pituitary tumor cells

Zinc is thought to be an integral part of nuclear receptor proteins, stabilizing them in a conformation required for binding to target genes. However, we have recently shown that restriction of zinc availability with a chelator (diethylenetriaminepenta-acetic acid, DTPA) enhances, rather than inhibits, the ability of thyroid hormone to induce growth hormone mRNA expression in GH3 rat pituitary tumor cells. In this report, we have extended these observations by showing that a prolonged (48 h) exposure to DTPA is required to see these effects. The induction by DTPA can be reversed by subsequent addition of zinc, but again, this reversal is slow. A second chelator, EDTA, can also induce growth hormone gene expression in the presence of thyroid hormone, though it is less potent than DTPA. Other agents which act via the nuclear receptor pathway, all-trans and 9-cis retinoic acid, also induce expression of growth hormone mRNA. Addition of DTPA amplifies these effects in a zinc-dependent manner. Thus chelation of zinc potentiates the action of ligands acting via nuclear receptors on growth hormone gene expression. The delayed nature of the response suggests an indirect effect.     

REGULATION OF GROWTH HORMONE GENE EXPRESSION BY RETINOIC ACID

Retinoic acid, acting in synergism with thyroid hormone, stimulates production of growth hormone in cultured pituitary cells. Evidence shows that retinoic acid produces this effect by binding to its nuclear receptor, a step followed by association of the retinoic acid-receptor complex with an element of the promoter of the growth homone gene, in concert with thyroid hormone.