BTBD10蛋白在大鼠胰岛和INS-1细胞株的表达

目的观察BTBD10蛋白在大鼠胰岛和INS-1细胞株的表达。方法利用构建好的BTBD10多克隆抗体,采用多重免疫荧光技术和激光共聚焦显微镜观察BTBD10在3月龄Fischer344大鼠的胰腺组织和大鼠胰岛β细胞株INS-1细胞中的表达。结果 BTBD10蛋白定位在大鼠胰腺组织的胰岛β细胞中,与胰岛素的定位重叠,而在胰腺的外分泌腺和胰岛α细胞中无表达,同时显示BTBD10定位在大鼠胰岛β株INS-1细胞的细胞浆中,表达量高。结论 BTBD10特异性表达于大鼠胰岛β细胞中,提示BTBD10可能与胰岛β细胞功能和胰岛素分泌有关。     

RNA interference targeting mu-opioid receptors reverses the inhibition of fentanyl on glucose-evoked insulin release of rat islets

Background Mu opioid receptor plays an important role in many physiological functions. Fentanyl is a widely used opioid receptor agonist for analgesia. This study was conducted to test the role of mu-opioid receptor on insulin release by determining whether fentanyl affected insulin release from freshly isolated rat pancreatic islets and if small interfering RNAs （siRNA） targeting mu-opioid receptor in the islets could knock down mu-opioid receptor expression.Methods Islets were isolated from ripe SD rats＇ pancreas by common bile duct intraductal collagenase V digestion and purified by discontinuous Ficoll density gradient centrifugation. The siRNA knock-down of mu-opioid receptor mRNA and protein in islet cells was analyzed by semi-quantitative real time-PCR and Western blotting. After siRNA-transfection for 48 hours, the islets were co-cultured with fentanyl as follows： 0 ng/ml, 3 ng/ml and 30 ng/ml for 48 hours. Then glucose-evoked insulin release was performed. As a control, the insulin release was also analyzed in islets without siRNA-trasfection after being co-cultured with fentanyl for 48 hours.Results After 48 hours of transfections, specific siRNA targeting of mu-opioid receptors produced significant reduction of mu-opioid receptor mRNA and protein （P ＜0.01）. Fentanyl significantly inhibited glucose-evoked insulin release in islets in a concentration dependent manner （P ＜0.01）. But after siRNA-transfection for 48 hours, the inhibition on glucose-evoked insulin reiease was reversed （P ＜0.01）.Conclusions RNA interference specifically reduces mu-opioid receptor mRNA and protein expression, leading to reversal of the fentanyl-induced inhibition on glucose-evoked insulin release of rat islets. The activation of opioid receptor induced by fentanyl functions to inhibit insulin release. The use of RNAi presents a promising tool for future research in diabetic mechanisms and a novel therapy for diabetes.     

VEGF对大鼠胰岛瘤细胞增殖、凋亡及胰岛素分泌功能的影响

目的 探讨血管内皮生长因子（vascular endothelial growth factor, VEGF）对大鼠胰岛瘤细胞（INS-1）增殖、凋亡、胰岛素分泌以及相关基因表达的影响。方法 用不同浓度（0、40、80、160 ng/mL)VEGF对大鼠INS-1细胞进行处理,采用CCK-8试剂盒检测INS-1细胞增殖,用Annexin Ⅴ及碘化丙啶(PI)双染试剂检测细胞凋亡;INS-1细胞经VEGF处理后做标准葡萄糖刺激的胰岛素分泌实验, ELISA法检测胰岛素,实时定量PCR技术检测胰岛分泌过程中相关基因表达,Western blot检测VEGF对Insulin蛋白表达的影响。结果 不同浓度VEGF对INS-1细胞作用24 h、48 h、72 h,其细胞活性均无明显变化（P>0.05）。但当VEGF浓度为80 ng/mL和160 ng/mL时对细胞凋亡具有抑制作用(PSur)、内向整流性钾离子通道基因 (inwardly rectifying potassium channel 6.2, Kir6.2)的表达随VEGF浓度增高呈下降趋势,葡萄糖激酶基因（glucokinase,GCK）的表达先降低后升高,葡萄糖转运蛋白基因2（glucose transporter 2,Glut2）表达呈先升高后降低趋势,Insulin蛋白的表达量随VEGF浓度增高呈逐渐下降趋势。结论 VEGF在高糖状态下对细胞凋亡和胰岛素分泌有抑制作用,为探索VEGF在糖代谢中的作用提供了新的线索。     

高血糖对体外培养的胎鼠胰岛Pdx-1基因的影响

目的：研究在体外培养时，高血糖对胎鼠胰岛胰和十二指肠同源盒基因-1（Pdx-1)和胰岛素基因的影响。方法：胶原酶法分离胎鼠胰岛，分别在葡萄糖浓度为5.5mmol/L,11.1mmol/L,33.3mmol/L的条件下培养24h。采用胰岛素含量测定、胰岛素释放实验评价胰岛功能；免疫细胞化学染色检测Pdx-1在细胞内的表达；逆转录PCR（RT-PCR）检测Pdx-1和胰岛素mRNA表达水平。结果：高血糖组1（11.1mmol/L)胎鼠单位重量胰岛细胞内胰岛素水平和刺激指数高于低糖组（5.5mmol/L)和高血糖组2（33.3mmol/L)。而且，高血糖组胎鼠胰岛Pdx-1蛋白的核移位率和mRNA表达水平均高于低糖组，但是高糖组2胰岛素mRNA表达低于高血糖组1，与低糖组无显著性差异。结论：高血糖刺激可以促进胎鼠Pdx-1表达和转录活性，可能是影响胰岛功能和β细胞对葡萄糖刺激敏感性增加的原因之一。     

免疫抑制剂依维莫司对大鼠胰岛细胞的毒性作用

目的 观察依维莫司等免疫抑制剂对大鼠胰岛瘤细胞(INS-1)和SD大鼠正常胰岛细胞代谢活性和功能的影响,旨在探讨依维莫司在胰岛移植免疫抑制治疗中的安全性和可行性.方法 不同浓度梯度免疫抑制剂依维莫司、西罗莫司、环胞霉素A和霉酚酸酯处理INS-1和正常胰岛细胞,用MTT法检测细胞的代谢活性;用葡萄糖刺激胰岛素分泌实验检测胰岛细胞的胰岛素分泌功能.结果 临床血药浓度以上的依维莫司和西罗莫司高浓度组胰岛细胞增殖抑制率低于环胞霉素A和霉酚酸酯(P＜0.05);依维莫司在临床血药浓度范围和其它免疫抑制剂一样可以抑制胰岛细胞的胰岛素分泌功能,各组间的刺激指数差异无统计学意义.结论 依维莫司和西罗莫司对INS-1细胞及SD大鼠胰岛的毒性作用较小,环胞霉素A和霉酚酸酯对INS-1和SD大鼠胰岛具有较为明显的毒性作用,依维莫司有望作为新型免疫抑制剂应用于临床胰岛移植.     

硫氧环蛋白相互作用蛋白与糖尿病关系的研究

目的 研究高糖环境下INS-1细胞中硫氧环蛋白相互作用蛋白(thioredoxin interacting protein,TXNIP)的表达对胰岛素分泌的影响以及N-乙酰半胱氨酸(N-acetylcysteine,NAC)、艾塞那肽(Exenatide,Ex-4)的保护作用.方法 以含11.1 mmol/L葡萄糖的RPMI 1640培养液培养INS-1细胞,当细胞生长至80%融合时,分别转入含有4.0 mmol/L葡萄糖(NG组)、16.7 mmol/L葡萄糖(HG组)及16.7 mmol/L葡萄糖+10 mmol/L NAC(HG+N组)、16.7 mmol/L葡萄糖+100 nmol/L Ex-4(HG+E组)的RPMI 1640培养液中继续培养48 h;采用real-time PCR法检测TXNIP、胰岛素基因及胰岛素转录因子MafA的mRNA水平.结果 HG组与NG组比较,TXNIP mRNA的表达明显上升,胰岛素mRNA、MafA mRNA的表达均明显下降,差异均有统计学意义(均P<0.01).HG+N组、HG+E组与HG组比较,TXNIP mRNA的表达均明显下降,胰岛素mRNA、MafA mRNA的表达均明显提高,差异均有统计学意义(均P<0.01).结论 高浓度葡萄糖可通过介导TXNIP的过度表达而导致胰岛素基因及MafA表达下降;特异性地抑制高糖下TXNIP的过度表达可以恢复胰岛素基因及MafA的表达.     

单核细胞趋化蛋白-1通过促进胰淀素表达调控胰岛β细胞凋亡

目的观察单核细胞趋化蛋白-1(MCP-1)对胰岛β细胞凋亡的影响,并探讨其可能机制。方法体外培养大鼠胰岛β细胞株INS-1E,给予1ng/ml的MCP-1刺激48h后,real-time PCR及western blot检测细胞中Amylin的mRNA及蛋白表达水平,同时流式细胞仪检测细胞凋亡情况。细胞转染Amylin SiRNA,再给予MCP-1刺激,同样采用流式细胞仪技术检测细胞凋亡情况。结果 INS-1E细胞经MCP-1刺激后,细胞中Amylin的mRNA及蛋白表达水平均升高(P<0.05),细胞出现了凋亡现象。而预先转染了抑制Amylin表达的siRNA后再进行MCP-1的刺激,此时细胞的凋亡率低于单独刺激组(P<0.05)。结论 MCP-1通过促进胰淀素的表达调控胰岛β细胞的凋亡,从而影响血糖代谢。     

巢蛋白在大鼠胚胎、新生及成年胰腺中的表达变化

目的：探讨巢蛋白(nestin)在胚胎后期、新生期、成年三阶段的核酸、蛋白水平表达的变化．方法：取三个发育时期的胰腺,应用RT—PCR、免疫组化的方法进行半定量、定位分析．结果：在胚胎后期、新生期、成年三阶段nestin在核酸、蛋白水平均有表达,阳性细胞主要分布在胰岛,在腺泡周围的外分泌中有少量分布．结论：随大鼠胰腺的生长发育,核酸、蛋白表达下调．胰岛内nestin阳性细胞数也呈下降趋势．     

Protection of rat islet viability following heme oxygenase-1 gene transfection via adenoviral vector in vitro

Objective： To investigate the effect of Heme oxygenase-1 （HO-1） gene transfection on the viability of cultured rat islets, and to explore the potential value of HO-1 gene in islet transplantation. Methods：Recombinant adenovirus vector containing human HO-1 gene（Ad-HO-1 ） or enhanced green fluorescent protein gene（Ad-EGFP） was generated by using AdEasy system respectively. The rat islets were transfected with Ad-HO-1, Ad-EGFP or blank vector and then cultured for 7 days. Transfection was confirmed by expression of EGFP and human HO-1 protein detected by fluorescence photographs and western blot, respectively. The insulin release upon different concentration of glucose stimulation was detected using insulin radioimmunoassay kit, and stimulation index（SI） was calculated. Glucose-stimulated insulin release was used ＇to assess islet viability. Results：Adenovirus vector successfully transferred HO-1 gene to rat islet cells in vitro, and the insulin release upon high level of glucose stimulation and stimulation index （SI） of Ad-HO-1-infected islets were significantly higher than those of Ad-EGFP-infected islets and control islets （P 〈 0.05）. Conclusion： Adenovirus-mediated HO-1 gene transfection is a feasible strategy to confer cytoprotection and therefore protect the viability of cultured rat islets.     

同型半胱氨酸对胰岛β细胞分泌胰岛素的影响

目的探讨同型半胱氨酸对胰岛β细胞的毒性作用。方法INS-1E细胞经传代培养2d后,在Krebs-Ringer缓冲液中37℃培养箱预培养30min,用含有葡萄糖和Hey的改良Krebs—Ringer缓冲液培养60min,留取上清液进行胰岛素测定。雌性NMRI小鼠,苯巴比妥腹腔麻醉,应用胶原酶技术消化胰腺分离胰岛,置于RPMI1640培养皿中在37℃培养箱（5％CO2,95％空气）过夜培养。次日在Krebs—Ringer缓冲液中37℃水浴培养箱预培养30min,分别把单个胰岛放入100μL含有葡萄糖和Hcy的改良Krebs—Ringer缓冲液37℃水浴培养箱培养60min,留取50μL上清液进行胰岛素测定。结果在中等浓度和高浓度的葡萄糖条件下Hcy均可降低INS-1E细胞和小鼠胰岛分泌胰岛素。结论Hcy抑制葡萄糖诱导的INS－1E细胞和小鼠胰岛的胰岛素分泌。     

糖尿病小鼠左肾被膜下胰岛细胞与胰腺外分泌细胞共同移植动物模型的建立

目的：建立糖尿病小鼠左肾被膜下同种异体胰岛细胞与胰腺外分泌细胞共同移植动物模型及探讨胰腺外分泌细胞对胰岛移植物的损伤作用.方法：（1）体内实验：采用胆总管内逆行灌注胶原酶联合淋巴细胞分离液的方法来分离纯化胰岛,人工挑取胰岛细胞并收集胰腺外分泌细胞.链脲佐菌素腹腔注射诱导BALB/C小鼠成为糖尿病小鼠.单纯移植组（n=10）每只小鼠于左肾被膜上极移植胰岛细胞250个,共同移植组（n =10）每只小鼠于左肾被膜上下极同时移植胰岛细胞250个和等体积的胰腺外分泌细胞,持续观测血糖及生命体征变化,1个月后切除左肾并继续检测血糖.（2）体外实验：利用双硫腙对胰岛进行特异性染色来计算胰岛产量及纯度,利用台盼蓝染色鉴定胰岛细胞的活性,以及用葡萄糖刺激胰岛素释放实验来检测胰岛功能.结果：（1）胰岛移植后,单纯移植组及共同移植组血糖均逐步降至正常,共同移植组较单纯移植组血糖恢复正常时间延迟,移植术后第2,3,4,5天,单纯移植组受鼠血糖低于共同移植组,差异有统计学意义（P＜0.05）.切除两组受鼠左肾3d后,两组受鼠血糖均＞21 mmol/L.（2）每只小鼠可获得150～200个高质量胰岛,纯度及活性均高于90％,葡萄糖刺激后胰岛素释放量明显增加（SI=2.90）.结论：（1）成功建立糖尿病小鼠左肾被膜下同种异体胰岛细胞与胰腺外分泌细胞共同移植动物模型.（2）胰腺外分泌细胞与胰岛细胞同时移植会延迟植入胰岛功能恢复正常的时间.     

低糖状态对大鼠增食欲素及受体的影响

目的　研究急性葡萄糖水平的下降对大鼠下丘脑及培养胰岛细胞中增食欲素 (orexin)及其受体(OX1 R、OX2 R)的影响。方法　应用单次皮下注射胰岛素并伴 (或不伴 )禁食的方法 ,构建急性低血糖大鼠模型 ;体外原代培养胰岛细胞并调整培养液的葡萄糖浓度 (8 3mmol L及 2 8mmol L) ;应用反转录 -聚合酶链反应 (RT PCR)检测下丘脑组织和胰岛细胞中orexin系统的变化。结果　在胰岛素 (伴禁食 )诱导的急性低血糖大鼠模型中 ,下丘脑orexin的mRNA表达较对照组增加约 1 5 0 % (P <0 0 1 ) ,OX1 R的mRNA表达减少 30 % (P <0 0 1 ) ,但是OX2 R的mRNA表达没有明显变化 (P >0 0 5 ) ;在培养胰岛细胞体外实验中 ,培养基中葡萄糖浓度由 8 3降至 2 8mmol L ,6h后胰岛细胞的orexinmRNA表达增加 1 0 0 % (P <0 0 1 ) ,而OX1 RmRNA表达对培养基中葡萄糖浓度的急性波动不敏感。结论　急性葡萄糖水平降低将刺激大鼠下丘脑中orexin的表达 ,其受体的变化相反 ;进食将会抑制orexin系统的这一反应。体外实验中发现培养胰岛细胞在葡萄糖浓度改变时发生类似变化     

EFFECTS OF ACUTE HYPOGLYCEMIA ON THE OREXIN SYSTEM IN RAT

OREXIN isa kind of new neuropeptideisolated from rathypothalamus, which involvedin many physiologicalregulationprogressesvia orexin1receptor(OX R )and orexin2 receptor(OX R ).The physio- 1 2logicalfunctionoforexinisstillnotcompletelyknown ,butitisidentifiedthatorexinis involvedinmany physiologicalprogressesuchasfeeding,sleep,and stress.1However ,itisstillunknown abouttheregulationoforexinsystemby hypo-thalamus,theregulationtopancreasby orexinsystem,and the regulationbetween orexin,bloodglu…     

成年大鼠非胰岛内Nestin阳性细胞的体外分离、培养及分化

目的:建立成年大鼠胰腺非胰岛内Nestin阳性细胞的体外分离培养及分化的方法。方法:采用胰管内注入胶原酶消化法分离3只成年大鼠胰腺组织,并经含10%胎牛血清RPMI 1640液（pH 7.6）体外培养,36 h后弃去悬浮细胞及胰岛,改用无10%胎牛血清RPMI 1640液（pH 7.4）加bFGF、EGF及N₂添加剂培养,18～22 d后收集新生类胰岛样细胞团并传代培养。挑选新分离的胰岛和新生类胰岛样细胞团每次各40个,共3次,采用¹³¹Ⅰ放射免疫法测定分离的胰岛及新生类胰岛样细胞团的胰岛素分泌量,并计算葡萄糖刺激指数（SI）;免疫荧光细胞化学法检查贴壁细胞及传代后的新生类胰岛样细胞团Nestin阳性细胞的表达。 结果:胰管内注入胶原酶消化法可获得功能、形态良好的胰岛;分离后胰腺组织在pH 7.6的10%胎牛血清RPMI 1640液培养条件下,36 h内胰岛细胞不贴壁,贴壁细胞中大多数表达Nestin阳性细胞,无胰岛素和胰高血糖素表达,但Nestin表达不一,培养18～22 d可见新生类胰岛样细胞团出现,新生类胰岛样细胞团传代后仍可见Nestin阳性细胞。新分离的40个胰岛在含糖3.3、16.7 mmol•L^-1培养液中胰岛素分泌量为(63.6±4.0)、(202.2±14.8)mIU•L^-1;而新生的40个类胰岛样细胞团胰岛素分泌量为(3.5±0.2)、(3.3±0.2)mIU•L^-1,差异有显著性（P<0.001）。 结论:胰管内注入胶原酶消化法可获得功能、形态良好的胰岛;在pH 7.6条件下可分离培养出成年大鼠胰腺非胰岛内Nestin阳性细胞,经无血清培养形成的类胰岛样细胞团,可传代培养,并表达胰岛素。胰腺非胰岛内Nestin阳性细胞具有胰腺干细胞特点。     

高浓度芬太尼抑制体外培养大鼠胰岛葡萄糖刺激胰岛素分泌

目的研究高浓度芬太尼对大鼠胰岛的损伤作用。方法通过用胶原酶V液灌注分离成年SD大鼠胰岛,不连续密度梯度离心法纯化胰岛。然后将胰岛分为空白对照组和处理组,处理组与20ng／ml的芬太尼在静态条件下共同培养24h和后,检测低高浓度葡萄糖（2．8和16．7mmol／L）刺激胰岛素释放试验,细胞内cAMP及蛋白含量,电子显微镜检测胰岛细胞。结果高浓度的芬太尼明显抑制大鼠胰岛的葡萄糖刺激胰岛素释放量,及细胞内cAMP的含量,电子显微镜检测显示高浓度芬太尼对大鼠胰岛具有损伤作用。结论高浓度芬太尼抑制体外培养大鼠胰岛素的分泌,并且对鼠胰岛细胞具有一定的损伤作用。     

Regulation of leptin on insulin secretion and sulfonulurea receptor 1 transcription level in isolated rats pancreatic islets

Objective To investigate the regulation of leptin on insulin secretion and expression of ATP-sensitive potassium channel subunit sulfonulurea receptor 1 (SUR1) mRNA, and to determine whether the effects of leptin are mediated through known intracellular signaling transduction.Methods Pancreatic islets were isolated by the collagenase method from male SD rats. The purified islets were incubated with different concentrations of leptin for 2 h in the presence of different concentrations of glucose. Insulin release was measured using radioimmunoassay. Expression of SUR1 mRNA was detected by RT-PCR.Results In the presence of leptin 2 nmol/L, insulin release was significantly inhibited at either 11.1 or 16.7 mmol/L glucose concentration (both P<0.05), but insulin release was not altered at glucose of 5. 6 mmol/L physiological concentration. The dose-response experiment showed that the maximal effect of leptin on insulin secretion achieved at 2 nmol/L. Exposure of islets to 2 nmol/L leptin induced a significan     

Activated pancreatic stellate cells can impair pancreatic islet function in mice

Background

Pancreatic or islet fibrosis is often associated with activated pancreatic stellate cells (PSCs). PSCs are considered not only to promote fibrosis, but also to be associated with glucose intolerance in some diseases. We therefore evaluated morphological and functional relationships between islets and PSCs in the normal mouse pancreas and transplanted islets.

Methods

Immunohistochemistry was used to map the presence of PSCs in the normal mouse pancreas and islets implanted under the renal capsule. We isolated and cultured mouse PSCs and characterized them morphologically by immunofluorescence staining. Furthermore, we measured their cytokine production and determined their effects on insulin release from simultaneously cultured islets.

Results

PSCs were scattered throughout the pancreas, with occasional cells within the islets, particularly in the islet capsule. In islet transplants they were found mainly in the graft periphery. Cultured PSCs became functionally activated and produced several cytokines. Throughout the culture period they linearly increased their production of interleukin-6 and mammalian keratinocyte-derived chemokine. PSC cytokine production was not affected by acute hyperglycemia. Syngeneic islets co-cultured with PSCs for 24–48 h increased their insulin release and lowered their insulin content. However, short-term insulin release in batch-type incubations was unaffected after 48 h of co-culture. Increased islet cell caspase-3 activation and a decreased islet cell replication were consistently observed after co-culture for 2 or 7 days.

Conclusion

Activated PSCs may contribute to impaired islet endocrine function seen in exocrine pancreatitis and in islet fibrosis associated with some cases of type 2 diabetes.     

大鼠INS-1细胞中IGFBP-2 mRNA的表达调控

目的:研究大鼠胰腺肿瘤β-细胞(INS-1)中,葡萄糖(Glucose)、胰岛素(Insulin)和生长激素(GH)对胰岛素样生长因子结合蛋白-2(IGFBP-2)基因的表达调控,探索IGFBP-2基因调节机制及其在维持正常胰腺细胞生理功能中的作用.方法:RNA印迹法(Northern blotting)检测INS-1细胞IGFBP-2 mRNA的表达,酶标法测定INS-1细胞胰岛素分泌量.结果:葡萄糖对IGFBP-2 mRNA调节作用不同;高浓度(10mmol/L)葡萄糖条件下,胰岛素分泌量增加,而IGFBP-2mRNA表达被抑制;低浓度(1～5.6 mmol/L)葡萄糖条件下,胰岛素分泌量无显著性变化,IGFBP-2 mRNA正常表达.INS-1细胞在不完全培养液中,加入GH培养,在不同时间间隔提取培养液进行IGFBP-2 mRNA检测,结果发现,培养16 h以上,IGFBP-2 mRNA表达开始显著下降.外源胰岛素抑制IGFBP-2 mRNA的表达.结论:葡萄糖和生长激素对INS-1细胞中IGFBP-2 mRNA表达的抑制作用是通过胰岛素调控的.     

高脂饮食肥胖大鼠胰岛细胞胰岛素抵抗机理的探讨

目的探讨高脂饮食诱导的肥胖大鼠在具有外周胰岛素抵抗(IR)的情况下,胰岛胰岛素、胰高血糖素的分泌和合成功能,高糖刺激下胰高血糖素和胰岛素的分泌以及胰岛内胰岛素信号转导分子的改变。方法30只雄性Wistar大鼠随机分为高脂饲料喂养的肥胖组和普通饲料喂养的对照组,每组各15只,共喂养20周。采用胰腺组织匀浆,检测胰岛素和胰高血糖素的含量;胰岛细胞表面灌注检测高糖状态胰岛素和胰高血糖素的动态分泌变化;免疫组织化学染色及图像分析检测胰岛素受体(IRc)及胰岛素受体底物1、2(IRS1、IRS2)在两组大鼠胰岛的表达。结果(1)肥胖组胰岛素敏感指数(ISI)明显低于对照组,肥胖组血胰高血糖素水平和胰岛内的胰高血糖素水平均显著高于对照组(362pg/ml±58pg/mlvs291pg/ml±35pg/ml,P<0.05;442pg/ml±56pg/mlvs287pg/ml±48pg/ml,均P<0.05)。(2)肥胖组葡萄糖刺激的胰岛素分泌(GSIS)受损,16.7mmol/L葡萄糖可显著抑制对照组胰岛α细胞胰高血糖素的分泌,而在肥胖组这种抑制作用消失。(3)胰岛存在IRc、IRS1和IRS2的表达。肥胖组胰岛IRc、IRS2的表达较对照组胰岛分别低28%和22%(均P<0.01)。结论高脂饮食诱导的肥胖大鼠胰岛细胞的胰岛素信号转导通路受损,即在有外周IR的同时也具有胰岛内的IR,这可能是肥胖状态下胰岛细胞功能障碍的内在机制之一。