过氧化物酶体增殖物激活受体γ在垂体腺瘤中的表达

目的 通过检测过氧化物酶体增殖物激活受体γ(PPARγ)在人垂体腺瘤组织中的表达,探讨其在垂体腺瘤中的相关机制.方法 通过免疫组化法确定经手术切除的83例垂体腺瘤组织细胞来源;采用RT-PCR、适时定量PCR检测研究83例垂体腺瘤组织及6例正常垂体组织PPARγ的mRNA表达量,采用Western blot法检测组织PPARγ蛋白质表达水平,分析不同类型垂体腺瘤组织之间核酸及蛋白水平表达量的差异.结果 GH腺瘤17例、PRL腺瘤15例、ACTH腺瘤18例、多激素腺瘤(MCPAs)17例、无功能腺瘤(NFAs)16例及正常对照组6例;mRNA水平检测显示所有垂体腺瘤组织的表达量均高于正常对照组,其中GH腺瘤的表达量最高,与其他组比较P＜0.05;蛋白水平检测显示GH腺瘤、PRL腺瘤、ACTH腺瘤及MCPAs的表达量均高于正常对照组(P＜0.05),GH腺瘤的表达量最高,NFAs的表达量与正常对照组差异无统计学意义(P＞0.05).结论 PPARγ转录及蛋白表达水平在人GH、PRL、ACTH及MCPAs垂体腺瘤组织中高表达,该基因与垂体腺瘤有一定的相关性,而无功能垂体腺瘤在核酸水平的表达量增高,蛋白水平的表达量不高,可能与激素的分泌水平有关;在GH腺瘤中的表达量最高,且与其他组相比,差异有统计学意义(P＜0.05),说明该类肿瘤与PPARγ的关系最为密切,可能与生长激素能刺激PPARγ的表达有关.     

垂体腺瘤侵袭性与galectin-3蛋白表达及Ki-67标记指数的关系

目的探讨半乳糖凝集素-3（galectin-3）蛋白表达及Ki-67标记指数（Ki-67u）与垂体腺瘤侵袭性的关系。方法运用免疫组化sP法检测50例标本中galectin-3蛋白的表达及Ki-67LI,分析galectin-3蛋白的表达及Ki-67LI与垂体腺瘤侵袭性的内在关系。结果galectin-3蛋白表达局限于泌乳素（PRL）腺瘤、促肾上腺皮质激素（ACTH）腺瘤及部分多激素分泌型腺瘤,在其他类型垂体腺瘤中表达呈阴性;且即lectin-3在上述类型侵袭性腺瘤中的表达水平（galectin-3计分为3,264＋1．066）明显高于非侵袭性腺瘤（gaIectin-3计分为1．613±0．850）（P〈0．01）。Ki-67LI在侵袭性组和非侵袭性组分别为2．754±1．029和1．692±0：858,两组有显著性差异（P〈0．01）。在表达galectin-3蛋白的垂体腺瘤中其表达水平与Ki-67LI之间存在正相关性（r=0．916,P〈0．01）。结论在PRL、ACTH腺瘤及部分多激素分泌型腺瘤中,galectin-3蛋白的表达与Ki-67LI呈明显正相关性,同时检测二者可以作为评价此类型垂体腺瘤侵袭性的重要参考指标之一。     

Immunohistochemical studies on human pituitary gland and adenomas.

To study coexpression patterns in normal and adenomatous pituitaries, frozen (n = 4) and paraffin-embedded (n = 10), normal human glands and 34 pituitary adenomas were investigated, using immunoperoxidase and double-labeling immunofluorescence methods. Broad range monoclonal antibodies (mAB) against cytokeratins (CK) (lu-5, A45-B/B3, AE1/3, CAM 5.2) as well as anti-CK18 (DC10) and anti CK19 (A53-B/A2) were compared with mAB's against vimentin, epithelial membrane antigen (EMA), epithelial sialomucin (ESM 140 C1), GFAP (GF-2), neurofilament (2F11), Leu-7 (HNK-1) and polyclonal AB's against pituitary hormones (ACTH, FSH, LH, TSH, GH, PRL). CK and vimentin coexpressing endocrine cells, mainly of the ACTH type, were observed in the pars intermedia in 5 of 14 normal pituitaries. All hormone producing cells expressed CK. The mAB A53-B/A2 (CK19) stained selectively the folliculo-stellate cells in frozen and paraffin sections. EMA, sialomucin and Leu-7 antigen localized to different structures of normal pituitaries. 25 of 34 pituitary adenomas exhibited CK positive tumor cells. Coexpression of vimentin or neurofilament protein was rare (2 cases of each). 9 CK negative adenomas were also negative for other intermediate filament proteins. 6 hormone producing adenomas showed unusual positivity for CK19. Whereas EMA and sialomucin reactivity disappeared in adenoma tissues, an enhanced Leu-7 antigen expression in the GH and prolactin adenoma group was noted. The heterogeneity of antigen expression seen in normal and neoplastic pituitary cells calls for further functional studies and usage of a broad range of mAB's against intermediate filaments in immunohistochemical studies of the pituitary.     

Silent mixed corticotroph and somatotroph macroadenomas presenting with pituitary apoplexy

We discuss three unique cases of pituitary macroadenoma presenting with pituitary hemorrhage but without typical endocrine symptomatology. Immunohistochemical analysis indicated positive reactivity for adrenocorticotropic hormone (ACTH) and growth hormone (GH), and in situ hybridization indicated the expression of proopiomelanocortin (POMC) and GH mRNA. We designated these cases silent mixed corticotroph and somatotroph adenoma. Patient 1 was a 30-year-old man, patient 2 was a 29-year-old woman, and patient 3 was a 59-year-old woman. All patients presented with a headache of sudden onset and visual disturbance. The patients did not exhibit typical Cushing's or acromegalic features. Serum ACTH level was remarkably elevated in patient 1, and slightly elevated in patients 2 and 3. In all patients, serum GH levels were within normal range and magnetic resonance imaging revealed an intra- and suprasellar mass with pituitary hemorrhage. Transnasal pituitary surgery in the three patients disclosed a pituitary adenoma producing ACTH and GH. In patient 2, the residual adenoma reappeared along with an intratumoral hemorrhage, and was resected by secondary transnasal surgery. Silent mixed corticotroph and somatotroph adenomas are characterized by the following: no endocrine symptoms; presentation dominated by mass effect symptoms; macroadenoma presenting with acute pituitary hemorrhage; and production of both ACTH and GH.     

儿童和青春期垂体腺瘤的经蝶手术治疗

目的探讨年龄小于17岁的儿童及青春期垂体腺瘤的诊断及其经蝶窦显微外科手术治疗。方法本组20例(垂体PRL腺瘤7例，ACTH腺瘤5例，GH腺瘤4例，无功能腺瘤4例)均行经蝶窦显微外科垂体腺瘤切除术。结果肿瘤全切除18例，部分切除2例；随访8个月～8年，治愈75％，缓解25％，复发5％；常见并发症为尿崩症(25％)和电解质紊乱(25％)。结论经蝶窦垂体腺瘤切除术是治疗儿童及青春期垂体腺瘤的安全有效的方法：     

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.     

Difference of lectin binding sites of secretory granules between normal pituitary and adenoma cells

Summary Electron-immunocytochemical staining with lectin (concanavalin A: Con A) binding sites analysis was applied to study secretory granules of human pituitary adenomas and surrounding normal pituitary tissue using post-embedded serial ultrathin sections. Twelve cases of human pituitary adenoma and three specimens of normal pituitary tissue surrounding adenomas were studied: the cases were operated on between 1982 and 1984. The tumors consisted of four prolactin (PRL)-, six growth hormone (GH)-, and two adrenocorticotropic hormone (ACTH)-producing adenomas.In parallel with the detection of Con A binding sites of secretory granules, their secreting hormones were characterized electron-microscopically with the immunocytochemical horseradish peroxidase (HRP) labeling using the avidin-biotin technique. The two cases of ACTH-producing adenomas showed either weak or negative reactions with Con A on secretory granules, while normal ACTH-producing pituitary cells showed strong reactions with Con A on every secretory granule observed. Large secretory granules of PRL- or GH-producing cells showed negative reactions with Con A both in the pituitary adenoma and normal pituitary, while some small granulated or sparsely granulated adenoma cells also showed strong reactions with Con A.The complexity of human pituitary adenomas is illustrated as well as the difference in biochemical structure of normal pituitary cells and pituitary adenoma cells secreting the same specific hormone.     

伽玛刀放射外科治疗垂体腺瘤的疗效评价

目的评价伽玛刀(Gamma Knife)放射外科治疗垂体腺瘤的疗效及安全性。方法对2010年1月~2013年12月期间采用OUR旋转式伽玛刀作为首选方法治疗的143例垂体腺瘤患者的临床资料进行回顾性研究,PRL型54例、GH型24例、ACTH型11例、混合型(GH+PPL)15例和无功能型(NFA)39例。肿瘤直径2 mm~64 mm(平均26.3 mm),30%~70%等剂量曲线包绕肿瘤,肿瘤平均周边剂量26.5Gy,平均中心剂量41.0Gy。对术后随访患者的临床症状、血液激素水平和鞍区MRI检查结果进行对比分析。结果随访期3~30个月,平均18月,临床症状改善或消失103例(72.0%),激素水平下降或恢复正常84例(80.8%),肿瘤缩小或消失87例(60.8%),平均肿瘤生长控制率为95.1%。结论伽玛刀放射外科对各种类型垂体腺瘤的治疗是安全有效的,能够改善和控制大部分患者的临床症状、激素水平和肿瘤生长。     

蛋白激酶C对生长激素释放激素调节人垂体腺瘤激素分泌作用的影响

目的旨在探讨蛋白激酶C调节剂对原代培养人垂体腺瘤细胞分泌生长激素和催乳素作用的影响。方法经原代培养的人垂体腺瘤细胞与佛波醇酯共同培养,通过放射免疫学方法检测生长激素和催乳素水平,评价佛波醇酯对生长激素释放激素调节垂体腺瘤激素分泌作用的影响;同时应用DNA序列分析确定gsp癌基因突变率。结果gsp癌基因鉴定显示,18例垂体腺瘤组织标本中6例gsp癌基因表达阳性,5例突变位于201密码子,1例位于207密码子。佛波醇酯强烈刺激生长激素和催乳素的分泌并增强生长激素释放激素的刺激分泌作用,最大效应浓度为100nmol/L,使生长激素分泌水平增加2～30倍;Staurosporine作用则相反,大多数肿瘤细胞表现为明显的抑制效应,而且与gsp癌基因不相关;联合应用生长激素释放激素和佛波醇酯后使刺激分泌的作用增强,但与gsp癌基因亦无关。结论蛋白激酶C可能参与垂体腺瘤激素分泌的调控。     

Effect of calcium channel antagonist (nicardipine) on growth hormone and prolactin secretion in pituitary adenomas

This study was designed to investigate the effect of calcium channel antagonist (nicardipine) on basal and bromocriptine-inhibited GH or PRL secretion in eight patients with pituitary adenomas (six GH producing adenomas and two prolactinomas). GH or PRL was measured in blood collected at intervals for 12 hours after oral administration of nicardipine (Nc) (40 mg) and/or bromocriptine (Br) (2.5 mg) in each case. In vitro, pituitary adenoma cells were incubated in media containing Nc (200 ng/ml) and/or Br (200 ng/ml) over a 72-h period, and then in drugs-free media for three days. Media were collected at 24-h intervals and assayed for GH or PRL. In three of six GH producing pituitary adenomas, GH secretion was inhibited by Nc both in vivo and in vitro. In prolactinomas, PRL secretion was inhibited by Nc in vitro, but in vivo, an increase of plasma PRL levels was observed after Nc administration in one of two cases. In two acromegalic patients and one patient with prolactinoma, Nc reduced the suppression of GH or PRL secretion induced by Br. These findings indicate that influx of extracellular calcium plays an important part in both GH and PRL secretion in functioning pituitary adenomas, and that Nc effects on GH and PRL secretion in pituitary adenomas by blocking of influx of calcium and/or antidopaminergic action. It is considered that the combined administration of calcium channel antagonist (Nc) and Br for acromegalic patients and administration of Nc for patients with prolactinomas should be avoided.     

Peroxisome proliferator-activated receptor gamma in the human pituitary gland: expression and splicing pattern in adenomas versus normal pituitary

Pituitary adenomas are slow-growing tumours arising within the pituitary gland. If secreting, they give rise to well-known syndromes such as Cushing's disease or acromegaly; when hormonally inactive, they come to clinical attention often with local mass effects or pituitary deficiency. Peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear hormone receptor with a key role in fat and glucose metabolism, but also involved in several neoplasia, has recently been detected in pituitary adenomas. In the present study, we evaluated the occurrence and splicing profile of PPARgamma in 43 cases of pituitary adenoma of different subtypes and compared it to 12 normal pituitary glands. By real-time polymerase chain reaction, PPARgamma was expressed as much in adrenocorticotrophic hormone (ACTH)-secreting and ACTH-silent adenomas as in controls, with a moderate underexpression in somatotrophinomas and prolactinomas and overexpression in 54% of nonfunctioning pituitary adenomas (NFPA). There was no apparent qualitative change in the splicing profile of pathological pituitary glands, nor was the presence of specific isoforms with dominant negative effects against PPARgamma detected. Western blotting revealed similar expression levels in the different subgroups of pituitary adenomas and normal glands. Immunohistochemistry confirmed PPARgamma expression in approximately one-half of analysed samples. The intra- and intergroup differences observed in pituitary adenomas may represent new elements in the process of understanding the different clinical responses of Cushing's and Nelson patients to PPARgamma-ligand treatment. Moreover, the higher level of PPARgamma expression detected in the NFPA subgroup may suggest its possible role as a molecular target in these pituitary adenomas, paving the way for investigations on the effectiveness of treatment with thiazolidinediones in such patients.     

垂体泌乳素腺瘤垂体特异转录因子表达的实验研究

目的研究垂体特异转录因子pit-1与PRL水平、肿瘤侵袭性的关系,探讨Pit-1在垂体瘤发病机制中的作用。方法免疫组化和RT—PCR分别测定Pit-1蛋白和pit—1 mRNA的表达,分析Pit-1与肿瘤侵袭性的关系。结果与对照组相比,Pit-1在PRL腺瘤中均有高表达,Pit-1、pit-1 mRNA表达与PRL水平呈正相关并与肿瘤侵袭性相关。结论Pit-1及pit-1 mRNA的表达在垂体PRL腺瘤发病机制中发挥一定作用。     

Inhibition of epidermal growth factor receptor stimulates prolactin expression in primary culture of the mouse pituitary gland

The roles of epidermal growth factor (EGF) in the regulation of prolactin (PRL) gene expression in the normal pituitary gland remain poorly understood. In the present study, the effects of EGF and an inhibitor of the EGF receptor, erlotinib, on PRL gene expression were examined both in the pituitary tumour cell line GH3 and in a primary culture of the mouse pituitary gland under similar experimental conditions. The results showed that EGF stimulated PRL expression in GH3 cells, but not in normal cells. Erlotinib was found to counteract EGF in GH3 cells inhibiting the PRL expression enhanced by EGF. By contrast, erlotinib induced an elevation in the PRL mRNA levels in the primary culture of the adult pituitary gland and the initiation of PRL production in the culture of the foetal pituitary gland in which PRL production had not yet occurred. Western blot analyses showed that EGF induced and erlotinib inhibited the activation of extracellular regulated protein kinase equally in GH3 and normal cells. These results suggest that the consequences of EGF receptor activation in normal PRL cells contradict those in adenomatous PRL cells.     

垂体生长激素腺瘤中gsp癌基因对GHSR-1a、Ghrelin mRNA表达的影响

目的 研究垂体生长激素(GH)腺瘤组织中Ghrelin、生长激素释放剂受体-1a亚型(GHSR-1a)mRNA的表达,并探讨其表达与gsp癌基因的关系.方法 采用PCR-DNA直接序列分析方法,观察43例垂体GH腺瘤组织中gsp癌基因的表达;应用实时荧光定量PCR检测Ghrelin和GHSR-1a mRNA的表达水平;统计学分析Ghrelin和GHSR-1a mRNA表达与gsp癌基因的关系.结果 Ghrelin mRNA表达在gsp癌基因阳性、阴性组织间差异无统计学意义(P＞0.05);gsp阳性组织中GHSR-1a mRNA表达明显高于gsp阴性组织(P＜0.05);gsp阳性、阴性腺瘤组织中GHSR-1amRNA与Ghrelin mRNA的表达均呈明显正相关(R=0.592或0.544,P＜0.05).结论 垂体GH腺瘤中gsp癌基因上调GHSR-1a mRNA的表达;而对Ghrelin mRNA表达无明显影响.gsp阳性、阴性腺瘤中Ghrelin均可正向调控GHSR-1a mRNA表达.     

Ghrelin stimulates adrenocorticotrophic hormone (ACTH) secretion by human ACTH-secreting pituitary adenomas in vitro

Ghrelin is a brain-gut peptide with wide-ranging endocrine, metabolic, cardiovascular and neural effects. Ghrelin, like its synthetic counterparts, the growth hormone (GH) secretagogues, has been shown to markedly stimulate adrenocorticotrophic hormone (ACTH) and cortisol secretion in humans and the ACTH-releasing effect of GH secretagogues is even greater in patients with pituitary ACTH-secreting tumours. Furthermore, these tumours synthesize ghrelin itself, suggesting an intrapituitary ghrelin circuit. The aim of the present study was to evaluate the effect of ghrelin on ACTH secretion by human pituitary corticotroph tumours in vitro to test the functionality of this circuit. Nine ACTH-secreting pituitary tumours (four microadenomas, five macroadenomas) were collected during surgery and incubated with 10-100 nM human ghrelin or with 10 nM human corticotrophin-releasing hormone (CRH). Control experiments were performed in rat anterior pituitary primary cultures. ACTH secretion was assessed after 4 h and 24 h incubation by immunometric assay. After 4 h of incubation with ghrelin, medium ACTH concentrations were two- to ten-fold higher compared to ACTH concentrations in unstimulated wells. The ACTH-releasing effect of ghrelin was significantly less than the response elicited by 10 nM CRH (up to 40-fold) Similar results were obtained after 24 h of incubation and a superimposable response pattern was observed in rat anterior pituitary primary cultures. The present study demonstrates that the endogenous GH secretagogue, ghrelin, stimulates ACTH secretion directly from human tumoural corticotrophs, as well as from normal rat pituitary, and indicates that the marked ACTH release elicited by ghrelin in patients with Cushing's disease in vivo is due, at least in part, to its action on the pituitary tumour. However, the reversal of the response pattern reported in vivo, with ghrelin proving a lesser stimulant than CRH in vitro, suggests that additional, suprapituitary mechanisms are involved in the in vivo response. Moreover, these data uphold the concept of a functional intratumoural ghrelin paracrine circuit in human corticotroph adenomas.     

120例垂体生长激素腺瘤及多激素腺瘤的临床和病理学特点分析

目的分析120例垂体生长激素（GH）腺瘤及多激素腺瘤患者的临床及病理学特征。方法回顾性分析120例免疫组化证实的垂体GH腺瘤及多激素腺瘤患者的临床资料,包括临床表现、生化改变、病理分型及侵袭性等。结果垂体腺瘤的好发年龄为20~50岁,男女发病比约为1：2,主要的临床表现为肢端肥大、头痛头晕、视力下降、视野缺损,女性患者表现有闭经、泌乳或月经紊乱。本组各种类型的垂体腺瘤的侵袭性比例：GH（＋）腺瘤为59.57%（28/47）、GH（＋）及PRL（＋）二种激素混合性瘤为35.48%（11/31）、GH（＋）和ACTH（＋）为33.33%（1/3）、GH（＋）和TSH（＋）为0（0/4）、GH（＋）和LH（＋）为33.33%（1/3）,以及GH（＋）及其它二种以上激素（＋）的多激素腺瘤34.38%（11/32）。单纯GH垂体腺瘤的侵袭性明显高于GH（＋）伴其它激素（＋）的垂体腺瘤的侵袭性（P0.05）。结论本组病例女性多于男性,单纯GH垂体腺瘤侵袭性明显高于其他类型的垂体腺瘤;病理免疫组化提示GH腺瘤除GH（＋）外,常常伴随其他激素（＋）。     

Neurotensin Receptor Down-Regulation Induced by Dexamethasone and Forskolin in Rat Hypothalamic Cultures is Mediated by Endogenous Neurotensin

Neurotensin (NT) has been shown to be involved in neuroendocrine regulation, and the presence of both the peptide and its receptors has been demonstrated in the hypothalamus. In the present study, we show that hypothalamic neurons in primary cultures express the neurotensin receptor (NTR) and we examined a possible regulation of this receptor by glucocorticoids and activators of adenylate cyclase. In the hypothalamic cultures, ¹²⁵I-NT bound to a single class of binding sites, presenting a selectivity similar to that observed for the high-affinity NTR previously described in the adult rat brain. Radioautographic studies demonstrated that these ¹²⁵I-NT binding sites were present on 3% of the neurons. A 48-h treatment with forskolin (fsk) decreased ¹²⁵I-NT binding by 30%. No effect of dexamethasone (dex) alone was found on that parameter. However, a combined treatment with both agents led to a 40% decrease in ¹²⁵I-NT binding, corresponding to a reduced number of binding sites, and to a 68% decrease in the amount of NTR mRNA. In parallel, the dex plus forsk treatment increased NT release in the incubation medium. Moreover, the decreases in ¹²⁵I-NT binding and NTR mRNA induced by this treatment were abolished in the presence of an anti-NT antibody or SR 48692, a non-peptidic antagonist of NTR, suggesting that the down-regulation of NTR observed after dex plus fsk treatment was mediated by the release of endogenous NT. Agonist-induced down-regulation of the NTR in this system was confirmed by the application of an exogenous NT analogue, JMV 449. The present findings indicate that, in hypothalamic cultures, dex and fsk indirectly down-regulate NTR expression via the release of endogenous NT.