南方鲇成鱼垂体的组织学与组织化学

运用组织学、组织化学技术对南方鲇成鱼垂体结构在生殖周期中的变化进行了研究.结果表明:南方鲇垂体为背腹型腺体,由神经垂体和腺垂体组成,神经垂体位于腺垂体中央;腺垂体前外侧部位于腺体前部,由PRL、ACTH细胞和少量GH、GTH细胞组成;中外侧部位于腺体中部及后部腹面区域,由GH、GTH和TSH细胞组成;中间部位于腺体后部背面,包括MSH、GTH细胞和首次在鱼类报道的大型泡状细胞.GTH和ACTH细胞结构在生殖周期中发生明显的变化,与生殖活动密切相关.     

三角鲂( Megalobrama terminalis) 脑垂体的超微结构

研究三角鲂(Megalobrama terminalis）脑垂体的超微结构，脑垂体由神经垂体和腺垂体构成，神经垂体组织中存在A1、A2和B型神经分泌纤维和一种脑垂体细胞，腺垂体由促肾上腺皮质激素分泌细胞(ACTH)、催乳激素分泌细胞(PRL)、生长激素分泌细胞(GH)、促甲状腺激素分泌细胞(TSH)、促性腺激素分泌细胞(GTH)、促黑色素分泌细胞(MSH)、PAS-反应细胞和一种非分泌类型的星状细胞(SC)构成，并讨论三角鲂神经垂体和腺垂体的结构特点。     

赤点石斑鱼脑垂体超微结构的初步研究

 应用透射电镜技术观察不同时期的性成熟赤点石斑鱼（Epinephelus akaara）脑垂体的超微结构。结果表明,性成熟赤点石斑鱼脑垂体近椭圆形,由神经垂体和腺垂体两部分组成。神经垂体主要由神经纤维、脑垂体细胞和微血管组成。其中神经分泌纤维存在A(A1、A2)和B型神经分泌纤维。腺垂体中外侧部（PPD）腺细胞由嗜酸性的GH细胞和嗜碱性的TSH细胞及GTH细胞3类细胞构成。在不同的时期,GTH细胞内的分泌颗粒明显不同。     

鲇脑垂体发生形态学的光镜和激光扫描共聚焦显微观察

应用光镜和激光扫描共聚焦显微镜时鲇脑垂体发生形态学进行观察：鲇脑垂体由两个不同部位的胚胎细胞形成,原始口腔背壁外呸层分离出来的细胞构成腺垂体的前外侧部(RPD)和中外侧部(PPD),从间脑腹面漏斗体分离出来的细胞卡构成腺垂体中间部(PI)及神经垂体．3d龄仔鱼脑垂体的形态业已建成,属前后型．5d龄仔鱼脑垂体可区分出神经垂体及腺垂体,腺垂体可区分出RPD、PPD、和PI3个区域,并开始出现毛细血管．此时,PPD内的生长激素(GH)细胞已经分化．11d龄稚鱼脑垂体中除PPD内GH细胞已分化外,未见其它促激素分泌细胞分化．15d龄稚鱼脑垂体PPD内的促肾上腺皮质素(ACTH)细胞及催乳激素(PRL)细胞已分化．20d龄稚鱼脑垂体内各种激素分泌细胞完全分化．11d龄以前仔鱼脑垂体属前后型,15d龄和20d龄的稚鱼脑垂体内RPD、PPD和P13部分呈直状排列．性成熟鲇脑垂体结构旱背腹型．     

瓦氏黄颡鱼对环境颜色无趋性行为

采用单因子试验设计,研究瓦氏黄颡鱼在早晚活动高峰期对6种环境颜色（黑、白、黄、蓝、绿、红）的偏好．结果：静水条件下,晚上和早上瓦氏黄颡鱼（体重为61．29±10．62g,体长为15±3．5cm,n=16）在6种不同环境颜色中活动时间平均百分比均不存在显著性差异（P〉0．05）;流水条件下（0．3m／s）,晚上和早上瓦氏黄颡鱼（n=7）在6种不同颜色底质中的活动时间平均百分比均不存在显著性差异P〉0．05）．研究结果表明瓦氏黄颡鱼在以上条件下没有明显环境颜色偏好．     

黄颡鱼脾脏和头肾的显微结构观察

运用组织学方法,观察了黄颡鱼脾脏和头肾的形态结构特征.结果表明,黄颡鱼脾脏小梁明显,实质由红髓和白髓构成,内含有大量的淋巴细胞和粒细胞等;黄颡鱼头肾与后肾明显分离,实质中无肾单位,主要由淋巴细胞、粒细胞、巨噬细胞和网状细胞等组成.     

生殖期间鳜脑垂体的超微结构观察

对生殖期间鳜脑垂体的超微结构进行观察．脑垂体由神经垂体和腺垂体两部分组成．神经垂体组织中存在2种类型的脑垂体细胞,并可以区分A1、A2和B 3种类型的神经分泌纤维,其终端轴突中具有不同直径和形态的分泌颗粒;B型纤维轴突中含有许多透明小囊泡．腺垂体由前外侧部、中外侧部和中间部构成,分布催乳激素分泌细胞、促肾上腺激素分泌细胞、生长激素分泌细胞、促甲状腺素分泌细胞、促性腺激素分泌细胞、促黑色素激素分泌细胞、PAS-高碘酸-雪夫反应细胞和一种非分泌细胞（星状细胞）类型．本文并讨论了繁殖季节排卵前后期鳜脑垂体的超微结构特点．     

南方鲶生殖周期中脑垂体和血清促性腺激素水平的含量变化

采用测定胡鲶科非洲鲶(Clariasgariepinus)GTH的放射免疫测定法,用标记鲤(Cyprinuscarpio)GTH的方法进行标记,测定了鲶科南方鲶(SilurusmeridionalisChen)生殖周期中的血清GTH水平和脑垂体GTH含量变化,以揭示其性腺发育、成熟过程中的内分泌调节机理.南方鲶血清中GTH水平的季节变化表现出与成熟系数相一致的变化趋势,周年中雌鱼血清GTH水平都高于雄鱼,雌雄鱼血清GTH水平在繁殖期间差异尤为显著.脑垂体中GTH含量也在生殖周期中具明显周期变化.在性腺发育晚期和成熟期雌鱼脑垂体的GTH含量明显高于雄鱼,而在其它性腺期雌鱼脑垂体的GTH含量仅略高于雄鱼,但雌雄鱼之间并无显著差异.     

4种幼鱼临界游泳速度和运动耐受时间的比较

以南方鲇(silurus meridionalis)、瓦氏黄颡鱼(Pseudobagrus vachelli)、青鱼(Mylopharyngodon piceus)、锦鲫(Caras-sius aumtus)等4种幼鱼为研究对象,在25℃条件下分别测定它们的临界游泳速度(Ucrit)和1.5倍Ucrit条件下的耐受时间.通过比较两种方式的游泳能力发现,4种幼鱼的Ucrit存在显著差异(p<0.05),其中南方鲇的Ucrit最低,而锦鲫的Ucrit最高,青鱼和瓦氏黄颡鱼的Ucrit则介于两者之间;南方鲇和瓦氏黄颡鱼之间的的耐受时间差异不显著,二者却显著高于青鱼和锦鲫,而锦鲫的耐受时间在4种幼鱼中最短(p<0.05).上述结果表明,南方鲇和瓦氏黄颡鱼在较高速度下的运动耐受能力更强,而临界游泳能力相对较低;锦鲫和青鱼则与此相反;它们的两种运动能力之间均存在着权衡,这种权衡可能与鱼类的生态习性之间存在着某种关联.     

南京师范大学生命科学学院科研快讯

正1.尹绍武教授课题组在瓦氏黄颡鱼低氧应激及种质改良研究方面取得重要进展近期,尹绍武教授课题组在瓦氏黄颡鱼低氧应激及遗传育种的研究中取得系列研究成果。题为"Integrated Analysis of mRNA-seq and miRNA-seq in the Liver of Pelteobagrus Vachelli in Response to Hypoxia"一文,作为标志性成果在2016年3月10日Nature集团出版的《Scientific Reports》(IF 5.578)上在线发表(www.nature.com/articles/srep22907)。利用转录组测序和miRNA测序技术,他们在黄颡鱼肝脏找到了参与缺氧应激反应的重要基因和miRNA,为后续研究肝脏应激反应的基因表达及其调控奠定     

Corticotropin releasing factor induction of leukocyte-derived immunoreactive ACTH and endorphins

Human peripheral leukocytes infected by virus or treated with endotoxin will, like unstimulated mouse spleen macrophages, synthesize immunoreactive corticotrophin (ir-ACTH) and endorphins. The ir-ACTH produced appears to be identical with authentic ACTH, while enough of the material has been produced in hypophysectomized mice infected with virus to demonstrate a steroidogenic response. Because the production of ACTH by in vivo pituitary cells and by leukocytes is suppressed by dexamethasone both in vitro and in vitro, suggesting that the production of ACTH and endorphins by leukocytes is indeed controlled, we have investigated the effects of corticotropin releasing-factor (CRF), which is known to regulate the pituitary production of both ACTH and beta-endorphin. We now report that the production of ACTH and endorphins by leukocytes is indeed induced by synthetic CRF and, in turn, suppressed by dexamethasone, suggesting that, as in pituitary cells, the proopiomelanocortin (POMC) gene may be expressed and similarly controlled in leukocytes.     

团头鲂脑垂体GTH细胞钙调素免疫电镜定位

本文运用免疫胶体金电镜定位技术对团头鲂(Megalobrama Ambly cephala)(?)垂体(?)性腺激素细胞进行了钙素(CaM)的超微结构定位。钙调素分别标记在与激素蛋白合成及分泌有关的细胞核、粗面内质网和分泌颗粒中,表明 CaM 参与激素的合成和转运作用。此外,促性腺激素分泌细胞中的大颗粒和小颗粒上均有 CaM,说明这两种颗粒具有共性,均参与激素的分泌活动,这一结果进一步弄清了大、小颗粒的性质,为鱼类的生殖生理及人工催产机理的研究提供了有价值的资料。     

Evidence for local stimulation of ACTH secretion by corticotropin-releasing factor in human placenta

The hypothalamic-pituitary-adrenocortical axis is activated in pregnancy and parturition. Levels of immunoreactive corticotrophin releasing factor (irCRF), immunoreactive adrenocorticotropic hormone (irACTH) and cortisol concentrations in maternal plasma are elevated throughout gestation, increase further during labour and fall precipitously after parturition. The placenta contains biologically active CRF and ACTH and it has been suggested that the placenta produces these peptides during pregnancy. Here we show that irCRF is located in the cytotrophoblast cells of placenta collected at term. Using a monolayer primary culture of human placental cells we have found that CRF stimulates secretion of peptides containing the ACTH sequence in the placenta in a dose-dependent manner, as it does in the pituitary. This effect is reversed by a CRF antagonist and is mimicked by dibutyryl cyclic AMP and forskolin. Glucocorticoids, which suppress the secretion of pituitary ACTH, were found to have no influence on release of irACTH by the placenta. Oxytocin and prostaglandins stimulate irACTH and irCRF secretion from cultured placental cells and the irACTH-releasing activity of two prostaglandins is partially reversed by a CRF antagonist. Thus CRF may be involved in the paracrine regulation of placental irACTH secretion.     

Increase of corticotropin-releasing factor staining in rat paraventricular nucleus neurones by depletion of hypothalamic adrenaline

In response to stress, adrenocorticotropic hormone (ACTH) is released by corticotrophs in the anterior pituitary under the control of several central and peripheral factors including corticotropin-releasing factor (CRF), which was recently isolated from the brain and sequenced. Immunocytochemical studies have shown that most of the CRF-containing cell bodies that project to the median eminence are present in the hypothalamic paraventricular nucleus (PVN). A dense PNMT(phenylethanolamine-N-methyltransferase)-containing fibre network was also observed in the same region--PNMT is the final enzyme in the biosynthesis of adrenaline and has been demonstrated in the brain. In the present study we found an association of adrenergic nerve fibres and CRF neurones by immunohistochemistry using antisera to PNMT and CRF. To examine the functional significance of the adrenergic projection to the PVN, we blocked the synthesis of adrenaline using a specific inhibitor of PNMT. The depletion of adrenaline resulted in an increase in CRF immunoreactivity. The present results suggest that, as well as catecholamines which regulate ACTH release at the anterior pituitary level via a beta 2-adrenergic receptor mechanism, central catecholamines (mainly adrenaline) also affect ACTH release through their action on CRF cells. Peripheral catecholamines seem to have a direct stimulatory effect on the pituitary corticotroph cells, whereas the present findings suggest that central adrenaline-containing neurones have an inhibitory role in the physiological response to stress.     

Circulating human pituitary pro-gamma-melanotropin enhances the adrenal response to ACTH

The amino-terminal region of the common corticotropin/beta-lipotrophin (beta-LPH) precursor has been identified in the AtT-20 mouse tumor cells as a glycopeptide with an apparent molecular weight of 16,000 (the '16K fragment'). A third melanotropin core sequence or gamma-MSH similar to that found in ACTH and beta-LPH was predicted to occur in this glycopeptide from the complementary DNA sequence of mRNA isolated from bovine pituitary intermediate tissue. Recently, the mouse of 16K fragment has been found to have a small but significant potentiation on the corticosteroidogenesis elicited by ACTH in a static cell system, an effect that could be enhanced when the glycopeptide was pretreated with trypsin. This synergism could also be mimicked by synthetic gamma-MSH peptides in vitro and in vivo. We report here the potentiating properties of a naturally occurring human pro-gamma-MSH glycopeptide on the ACTH-induced steroidogenic response of isolated perfused rat and human adrenocortical cells.     

花鳗鲡重组促黄体生成素在毕赤酵母中的表达

 采用聚合酶链反应从花鳗鲡垂体cDNA中分别扩增出GTHα、LHβ基因,再利用搭桥技术,中间以linker将两个基因连接成单个基因LHβα。然后利用双酶切、连接,将LHβα基因连接到载体pPICZαA中,构建出促黄体生成素的酵母共表达载体pPICZαA-LHβα。再利用电转化法将其转入到酵母野生型菌株X-33中,在含不同浓度的zeocinYPDS平板上筛选高拷贝转化子,阳性克隆经φ=0.7%甲醇诱导表达,表达产物采用SDS-PAGE和western blot进行分析,得到所表达的产物相对分子质量约为45 000。