胰腺外分泌细胞的适应性细胞保护作用

用5％牛磺胆酸钠-胰蛋白酶溶液作为强刺激物直接注入大鼠胰导管系统,制成急性出血坏死性胰腺炎模型。若于48h前向胰导管内预先给予0.1％、0.2％或0.4％的低浓度牛磺胆酸钠-胰蛋白酶溶液作为弱刺激物,能使随后给予的强刺激物所致的损伤大大减轻,使病鼠死亡率由对照组的100％分别降低到27％、17％和17％;血清淀粉酶浓度升高的幅度由对照组的4680U/100ml血清降低到1990、2180和2710U/100ml血清。胰腺组织学切片检查可见,病变由急性出血坏死性胰腺炎转变为轻度急性胰腺炎或向慢性胰腺炎转化。这项结果提示:预先给予弱刺激可使胰腺外分泌细胞对随后给予的强刺激产生适应性细胞保护作用,其机制尚待探索。     

胰多肽对急性胰腺炎大鼠的细胞保护作用

用5%牛磺胆酸钠-胰蛋白酶溶液直接注入大鼠胰导管,制备成急性出血坏死性胰腺炎模型。由腹腔于制备前预防性地和制备后治疗性地结合注射剂量为3μg/kg 的牛胰多肽,能使病鼠的死亡率由对照的100%降到33%,已死鼠平均存活时间由对照的13±3小时延长到20±2小时,血清淀粉酶浓度升高的峰值降为对照的35%,胰腺组织学切片呈轻度急性胰腺炎或向慢性胰腺炎转化。单纯在制备前预防性地注射牛胰多肽或仅在制备后作治疗性注射,也有同样作用,但效果较差。这项结果提示,胰多肽对急性出血坏死性胰腺炎具有预防和治疗两方面的功效,即对胰腺有细胞保护作用。抑制胰酶的分泌和释放可能是它的作用机制之一。     

急性坏死性胰腺炎大鼠胰腺外分泌细胞中hsp70基因的表达

给大鼠胆胰管内逆行注射牛磺胆酸钠制备急性坏死性胰腺炎动物模型,采用Ｎｏｒｔｈｅｒｎ杂交及免疫组织化学方法检测了ｈｓｐ７０基因在胰腺外分泌细胞中的表达。Ｎｏｒｔｈｅｒｎ杂交分析发现,术后１ｈ即出现ｈｓｐ７０ｍＲＮＡ的高表达,然后开始下降,术后８－１６ｈ恢复至对照组水平。免疫组织化学检测发现,术后１ｈ即可见明显的ＨＳＰ７０蛋白染色,２ｈ最强,然后开始减弱,一直持续至１６ｈ,仍高于对照组水平;阳性染色位于腺泡细胞顶部并呈大颗粒状,而基底部、细胞核及腺泡腔内未见阳性信号。推测急性胰腺炎时胰腺外分泌细胞高表达ｈｓｐ７０基因,可能与其参与大量合成的胰酶的转运及抑制胰酶激活等保护作用有关。     

胰多肽

胰多肽(pancreatic polypeptide,简称PP)是一种主要从胰腺中提取出的具有36个氨基酸残基的激素。60年代末Kimmel等在提取鸡胰岛素时偶然发现了胰多肽,称它为鸟胰多肽(avian pancreatic polypeptide,简写APP)。与此同时,林从敏和Chance等在提纯牛胰高血糖素和胰岛素时也发现了PP,称之为牛胰多肽(bovine pancreatic polypeptide,     

牛胰多肽对急性胰腺炎大鼠胰组织中磷脂酶A和胰蛋白酶活性的影响

以0.25％牛磺胆酸钠-0.25％胰蛋白酶溶液注入大鼠胰导管制备急性(出血坏死性)胰腺炎模型。观察剂量为 3μg/kg的牛胰多肽(BPP)对胰腺炎大鼠胰组织磷脂酶 A(PA)活性、钙含量、胰蛋白酶活性以及血清α_1-抗胰蛋白酶抑制力(STIC)的影响。结果如下:1.在伴注BPP的胰腺炎组,PA 活性、钙含量、胰蛋白酶活性及STIC 分别降为胰腺炎组的51％(P<0.001),75％(P<0.001)、20％(P<0.001)以及24％(P<0.001);2.在伴注碳酰胆碱的胰腺炎组,上述四项指标的水平升高。但在伴注碳酰胆碱及BPP 两者的胰腺炎组却分别降至伴注碳酰胆碱的胰腺炎组的39％(P<0.005)、51％(P<0.001)、40％(P<0.001)以及 59％(P<0.001);3.在伴注Ca~(2 )的胰腺炎组,上述四项指标剧升,注射 BPP对其无影响。结果提示,BPP 能降低大鼠胰组织内磷脂酶A 和胰蛋白酶活性及胰内钙沉积量。机制可能与 BPP打断胰酶活化链有关,是否还影响腺泡细胞膜上M受体的功能,有待探讨。     

对牛胰多肽抑制胰酶分泌作用的离体研究

为探讨胰多肽抑制胰酶分泌的机制,我们利用大鼠离体胰腺泡制备观察了牛胰多肽(BPP)在细胞受体水平对氨甲酰胆碱等促分泌物作用的影响。实验结果显示,BPP 对氨甲酰胆碱诱导的胰腺泡淀粉酶分泌具有抑制作用,并存在剂量反应关系。BPP0.1μmol/L 和0.2μmol/L,可分别使氨甲酰胆碱诱导淀粉酶分泌的效价降低3倍和10倍;BPP 还可抑制氨甲酰胆碱刺激胰腺泡释放~(45)Ca。以上结果提示,BPP 对胰腺泡的胆碱能 M 受体具有拮抗作用。此外,BPP 对促胰液素及其同类激动剂和氨甲酰胆碱协同作用诱导的胰腺泡淀粉酶分泌具有抑制作用,提示胰多肽在整体对促胰液素诱导的胰酶分泌的抑制,可能是通过拮抗胰腺泡细胞上的 M 受体而抑制了促胰液素和胆碱能刺激协同作用引起的胰酶分泌。     

牛胰多肽(Bovine Pancreatic Polypeptide)和DMPC脂质体相互作用的荧光研究

本文用多种荧光探剂标记脂质体,通过荧光光谱、荧光强度以及荧光偏振的变化,阐明牛胰多肽与磷脂之间存在较强的结合,这种结合主要是静电相互作用与疏水相互作用.牛胰多肽与磷脂结合后,使膜结构稳定,这可能是牛胰多肽具有细胞保护作用的原因之一.     

四川短尾鼩肝脏和胰腺的组织解剖学研究

对四川短尾鼩肝脏和胰腺的组织解剖结构进行了研究,结果表明:肝脏分为4叶,它们的肝实质完全分开.肝小叶的分界极不明显,1个肝小叶内的肝细胞大小不一致,靠近中央静脉的肝细胞体积较小,而肝小叶外围的肝细胞体积较大.胰腺的形态松散,无法区分出胰头、胰体和胰尾.胰腺小叶非常明显,大小不等.胰腺的组织结构包括外分泌部和胰岛两部分.     

酪氨酸羟化酶在成年大鼠胰腺中的定位

目的:酪氨酸羟化酶(tyrosine hydroxylase,TH)是儿茶酚胺类递质合成的限速梅,儿茶酚胺类递质对胰腺内分泌细胞的功能具有重要的调控作用,本研究拟探讨酪氨酸羟化酶(tyrosine hydroxylase,TH)在成年大鼠整个胰腺的具体定位和表达.方法:取雄性成年大鼠胰腺,冰冻组织切片,应用免疫荧光技术观察酪氨酸羟化酶在整个胰腺中的表达分布情况,并进一步运用免疫荧光双标技术鉴定酪氨酸羟化酶是否与胰岛素、胰高血糖素、生长抑素以及胰多肽分别共定位于β细胞;α细胞;δ细胞及PP细胞,进一步确定合成酪氨酸羟化酶确切的细胞类型.结果:①在胰腺腺泡细胞胞浆中存在酪氨酸羟化酶的阳性表达颗粒.②分布于胰腺外分泌腺的神经纤维和胰岛的神经纤维中都有酪氨酸羟化酶的表达.③酪氨酸羟化酶与胰岛的四种内分泌细胞所合成的肽之间均没有共定位关系.结论:在胰腺,酪氨酸羟化酶只存在于胰腺外分泌腺的腺泡细胞胞浆内以及胰腺中的神经纤维中,而胰岛四种内分泌细胞中没有酪氨酸羟化酶,说明胰腺儿茶酚胺类神经递质一方面由胰腺外分泌部的腺泡细胞合成,另一方面来源于神经末梢的释放,而胰岛细胞不能合成儿茶酚胺类递质;该结果为进一步研究胰腺内、外分泌部之间的关系和儿茶酚胺对胰腺分泌功能的调节提供形态学证据.     

发现一个胰多肽家族的新成员——神经肽Y

自从Kimmel等(1968)在鸡胰腺中分离出鸡胰多肽(PP)以来,人们相继由哺乳动物的胰腺中分离出牛、猪、羊、狗和人的胰多肽,并确定PP是由36个氨基酸残基组成的多肽。其后(1980),在Mutt实验室又由猪十二指肠提取物中分离出一种与PP结构类似的36肽,命名为酪酪肽(PYY),所谓PP家族便开始形成。由于用鸡PP或牛PP抗血清进行免疫组织化学研究发现,PP样免疫活性物质广泛分布在中枢神经系统中,因而人们一向认为,哺乳类动物的脑中存在着一种与PP在化学结构上有一定联系的肽类物质。但用放射免疫测定法却未能测出鸡PP、牛PP免疫活性。因此,脑中PP样免疫活性的实质一直没有搞清楚。最近,Totemoto等又从猪脑中分离出一种新的神经肽,命名为神经肽Y(neuropeptide Y,NPY),     

牛胰多肽（BPP）二级结构的红外光谱和圆二色谱分析

牛胰多肽（ｂｏｖｉｎｅｐａｎｃｒｅａｔｉｃｐｏｌｙｐｅｐｔｉｄｅ,ＢＰＰ）是胰脏分泌的一种含有３６个氨基酸的多肽［１］,ＢＰＰ能预防和治疗由胆酸盐诱发的大鼠急性胰腺炎,具有细胞保护作用。本文用傅里叶变换红外光谱（ＦＴ－ＩＲ）和圆二色谱（ＣＤ）,对ＢＰＰ在水溶液中的二级结构进行了研究。两种方法的分析结果互相补充,进一步确定了ＢＰＰ在溶液状态的二级结构。本研究为进一步探讨ＢＰＰ抑制膜融合的机理打下了基础。     

The identification of the F-cell in the dog pancreas as the pancreatic polypeptide producing cell.

The endocrine cells of the processus uncinatus in the dog pancreas were investigated with special reference to the formerly known F-cell. The F-cell was detected frequently in the periphery of pancreatic islets as well as among exocrine tissue. In both localizations the F-cell shows similar ultrastructural features. Membrane-bound irregularly shaped secretory granules of variable electron density were seen. The cell possesses all features of an endocrine polypeptide secreting cell. Using the immunofluorescence and immunoperoxidase technique in the uncinate processus of the dog, we could reveal that the anti-sera against bovine pancreatic polypeptide (BPP) reacts with the cell which is localized at the same sites as the F-cell. We therefore conclude that the pancreatic F-cell is identical to the pancreatic polypeptide-producing cell. The other endocrine cell types of the dog pancreas are glucagon-producing A-cells, insulin-producing B-cells, and somatostatin-producing D-cells, as well as serotonin-producing EC-cells which are regularly present in the dog pancreatic islets and also scattered among exocrine tissue and the duct epithelial cells.     

血糖浓度对糖尿病大鼠胰腺外分泌功能的影响

用链佐霉素诱导大鼠产生尿病,其胰腺组织淀粉的含量降低,胆囊收缩素（ＣＣＫ－８）刺激所引起的胰淀粉酶分泌也明显降低。用一种可以降低糖尿病大鼠血糖,但不影响其血清胰岛素水平的药物－－钒酸钠灌胃,可翻转上述变化。体外实验分析表明,高糖可抑制胰腺泡蛋白质的合成,还可以引起胰腺泡膜丙二醛含量增加,从而提示,糖尿病大鼠胰外分泌功能障碍与血液葡萄浓度过高有密切关系。     

链脲佐菌素诱导糖尿病大鼠胰腺外分泌部A、B细胞密度的变化

本文应用A蛋白金银—过氧化物酶抗过氧化物酶(PAGS-PAP)双重染色法,观察了链脲佐菌素(streptozotocin,STZ)诱导的糖尿病大鼠胰腺外分泌部含高血糖素的单个A细胞(单A细胞)及合胰岛素的单个B细胞(单B细胞)密度的变化.在一次大剂量腹腔注射STZ后第5天和第10天,大鼠胰腺外分泌部单A细胞密度较对照组大鼠增加,而单B细胞密度在注射STZ后第5天较对照组大鼠减少,但在第15天与对照组大鼠接近.在第15天,一些单B细胞分布在靠近胰岛的腺泡中,岛周腺泡含单B细胞的胰岛百分率明显高于对照组.由于胰腺外分泌部的单A、单B细胞在分布特征上与中间细胞相似,在糖尿病时其数量变化也与中间细胞一致,因此,本研究所观察到的单A、单B细胞与前人报道的中间细胞有密切关系.上述单A、单B细胞密度的变化提示,在STZ诱导的糖尿病大鼠,胰腺中的B细胞被STZ破坏后,其外分泌部可能有某些细胞通过中间细胞向单A、单B细胞发生了转化或者单A、单B细胞即此转化过程中的中间细胞.     

PANCREATIC MICROSOMES : AN INTEGRATED MORPHOLOGICAL AND BIOCHEMICAL STUDY

The pancreatic exocrine cell of the guinea pig has a voluminous endoplasmic reticulum distinguished by extensive association with small, dense particles, and by its orderly disposition in the basal region of the cell. In addition to the small, (~15 mµ), dense particles attached to the limiting membrane of the endoplasmic reticulum, numerous particles of similar appearance are found freely scattered in the cytoplasmic matrix. The various cell structures of pancreatic exocrine cells can be satisfactorily identified in pancreatic homogenates. The microsome fraction consists primarily of spherical vesicles (80 to 300 mµ), limited by a thin membrane (7 mµ) which bears small (~15 mµ) dense particles attached on its outer surface. The content of the microsomal vesicles is usually of high density. Pancreatic microsomes derive by extensive fragmentation mainly from the rough surfaced parts of the endoplasmic reticula of exocrine cells. A few damaged mitochondria and certain dense granules (~150 mµ) originating probably from islet cells, contaminate the microsome fraction. Pancreatic microsomes contain RNA, protein, and a relatively small amount of phospholipide and hemochromogen. They do not have DPNH-cytochrome c reductase activity. In six experiments the RNA/protein N ratios were found grouped around two different means, namely 0.6 and 1.3. Pancreatic microsomes are more labile than liver microsomes but react in a similar way to RN-ase-(loss of the particulate component and RNA), and deoxycholate treatment (loss of the membranous component and of phospholipide, hemochromogen, and most of the protein). Postmicrosomal fractions consisting primarly of small (~15 mµ), dense particles of ribonucleoprotein (RNA/protein N ratio = 1 to 2) were obtained by further centrifugation of the microsomal supernatant. The small nucleoprotein particles of these fractions are frequently found associated in chains or clusters.     

Immunohistochemical study on the endocrine pancreas of cattle with special reference to coexistence of serotonin and glucagon or bovine pancreatic polypeptide

Bovine pancreatic endocrine cells were investigated by light microscopic immunohistochemistry. Serotonin-immunoreactive cells as well as insulin-, glucagon-, somatostatin-, bovine pancreatic polypeptide (BPP)-immunoreactive cells were detected in the pancreatic islets. Generally, insulin-immunoreactive cells were distributed throughout the islet and the others took peripheral location. Since the distribution and shape of serotonin-immunoreactive cells were very similar to glucagon- and BPP-immunoreactive cells, serial sections were restained by using the elution method. All glucagon- and BPP-immunoreactive cells also showed serotonin immunoreactivity but glucagon and BPP immunoreactivities were never observed to be colocalized in the same cell. A small number of serotonin-immunoreactive cells were observed that showed serotonin immunoreactivity only.     

Reduced Pancreatic Exocrine Function and Organellar Disarray in a Canine Model of Acute Pancreatitis

The aim of the present study was to investigate the pancreatic exocrine function in a canine model and to analyze the changes in organelles of pancreatic acinar cells during the early stage of acute pancreatitis (AP). AP was induced by retrograde injection of 5% sodium taurocholate (0.5 ml/kg) into the main pancreatic duct of dogs. The induction of AP resulted in serum hyperamylasemia and a marked reduction of amylase activity in the pancreatic fluid (PF). The pancreatic exocrine function was markedly decreased in subjects with AP compared with the control group. After the induction of AP, histological examination showed acinar cell edema, cytoplasmic vacuolization, fibroblasts infiltration, and inflammatory cell infiltration in the interstitium. Electron micrographs after the induction of AP revealed that most of the rough endoplasmic reticulum (RER) were dilated and that some of the ribosomes were no longer located on the RER. The mitochondria were swollen, with shortened and broken cristae. The present study demonstrated, in a canine model, a reduced volume of PF secretion with decreased enzyme secretion during the early stage of AP. Injury of mitochondria and dilatation and degranulation of RER may be responsible for the reduced exocrine function in AP. Furthermore, the present model and results may be useful for researching novel therapeutic measures in AP.     

Anglerfish islets contain NPY immunoreactive nerves and produce the NPY analog aPY

It has recently been demonstrated that aPY, a peptide which has significant homology with neuropeptide Y (NPY) is present in extracts of anglerfish islets. The purpose of this study was to determine whether cells or nerves which contain NPY-like immunoreactivity could be identified in anglerfish islet tissue and whether aPY is synthesized by this tissue. Antisera against bovine pancreatic polypeptide (BPP), NPY and the 200 kd neurofilament polypeptide were used for immunohistochemical analysis of islets. Identical cells were stained by both the NPY and BPP antisera. The NPY and 200 kd neurofilament antisera also labeled nerve fibers in the tissue which were not stained with the BPP antiserum. The nature of the NPY-like peptide synthesized in islet cells was determined by subjecting differentially radioactively labeled Mr 2,500-8,000 peptides from islet extracts to reverse phase HPLC. Labeled aPY was unequivocally identified in the extracts and was labeled appropriately (as predicted from its sequence) with 13 different radioactive amino acids. These results demonstrate that one form of NPY-like peptide synthesized in anglerfish islets is aPY. The form of NPY-like peptide which was immunolocalized in nerves remains to be determined.     

Immunohistochemical study of the distribution of endocrine cells in the gastrointestinal tract of the camel (Camelus bactrianus)

The regional distribution and relative frequency of endocrine cells in the gastrointestinal tract of the camel, Camelus bactrianus, were investigated using immunohistochemical methods. Ten types of immunoreactive (IR) endocrine cells were identified in this study. Among these cell types, only serotonin- and somatostatin-IR cells were detected in almost all regions of the gastrointestinal tract. Most of the cell types showed peak density in the pyloric gland region. The others showed restricted distribution: gastrin, cholecystokinin (CCK), motilin, bovine pancreatic polypeptide (BPP), and (gastric) substance P in the stomach; gastrin, CCK, BPP, gastric inhibitory polypeptide (GIP), glucagon, peptide tyrosine tyrosine (PYY) and substance P in the small intestine; and CCK, motilin, BPP, and PYY in the large intestine. Fundamentally the distribution pattern of endocrine cells in the gastrointestinal tract of the camel is similar to that of cattle. The distribution and frequency of endocrine cells in the glandular sac region are the same as those of the cardiac gland.