选择性PI3K-Akt通路缺陷参与有生长追赶SGA大鼠胰岛素抵抗的发生机制

目的:研究有生长追赶的小于胎龄个体(SGA)骨骼肌组织胰岛素受体后信号分子的变化,探讨其胰岛素抵抗的发生机制。方法:应用孕鼠全程饮食限制法建立SGA大鼠模型。4周龄有生长追赶SGA(CUG-SGA)和无生长追赶SGA(NCUG-SGA)幼鼠随机分为对照组和胰岛素激发组,并设适于胎龄(AGA)组为对照。测定各组血糖和胰岛素(INS)浓度,计算胰岛素抵抗指数(HOMA-IR)和胰岛β细胞功能指数(HOMA-β)。应用Westernblotting测定各组腓肠肌组织胰岛素受体后信号分子胰岛素受体底物1(IRS1)、蛋白激酶B(Akt)和细胞外信号调节激酶(ERK)的表达及其磷酸化情况。结果:(1)CUG-SGA和NCUG-SGA幼鼠INS和HOMA-IR较AGA组明显增高(均P<0.01),CUG-SGA幼鼠的INS和HOMA-IR显著高于NCUG-SGA组。(2)CUG-SGA幼鼠肌肉组织基础状态下已有p-IRS1表达,INS激发后p-IRS1的表达无显著增加;p-Akt的表达在基础状态和INS激发后均较AGA和NCUG-SGA组显著减低;CUG-SGA基础状态亦有p-ERK表达,INS激发后p-ERK表达显著下降。相关分析显示在基础状态和INS激发状态,SGA幼鼠p-Akt与p-ERK表达呈显著负相关(r=-0.737,P<0.05;r=-0.658,P<0.05)。结论:(1)无论追赶与否,SGA个体生后均呈现胰岛素抵抗,CUG-SGA胰岛素抵抗程度更重。(2)IRS1-PI3K-Akt通路受损是胰岛素抵抗发生的重要的受体后机制;该通路阻断的同时发生Ras-MAPK-ERK通路信号的慢性激活,这可能是胰岛素抵抗同时发生生长追赶的分子机制。     

流体剪切应力对人脐静脉内皮细胞Pim-1基因表达的影响

目的　探讨流体剪切应力对人脐静脉内皮细胞（HUVECs）中Pim-1基因表达的影响及可能的信号机制。 方法　酶消化法分离健康产妇新鲜脐静脉获取原代HUVECs,应用平行平板流动腔系统给HUVECs加载不同时间（1、4、6 h）和不同大小（0.5、1.5、3.0 Pa）的层流剪切应力,用实时定量RT-PCR检测Pim-1基因的表达水平,用蛋白质印迹法检测p-Akt和p-STAT3的表达水平,利用Wortmannin (PI3K抑制剂)、 Deguelin (Akt抑制剂) 和AG490 (JAK抑制剂) 信号阻断剂探讨信号转导途径。 结果　HUVECs在1.5 Pa 剪切应力作用4 h后Pim-1基因表达明显增加。不同强度的切应力均会刺激Pim-1基因的表达,其中3.0 Pa表达最强。切应力能显著激活p-Akt和p-STAT3的表达。AG490可以明显抑制Pim-1的表达,而Wortmannin和Deguelin增强Pim-1的表达。 结论　流体剪切应力可诱导HUVECs中Pim-1基因表达,其表达量与刺激时间和剪切应力的强度密切相关,这种作用可能通过JAK/STAT3和PI3K/Akt信号通路调节。     

甘氨酸对3T3-L1脂肪细胞胰岛素抵抗的影响

目的：探讨甘氨酸对3T3-L1脂肪细胞胰岛素抵抗的影响及其机制。方法:诱导分化3T3-L1脂肪前体细胞为成熟的脂肪细胞，肿瘤坏死因子α（TNF-α）诱导建立脂肪细胞的胰岛素抵抗模型，以罗格列酮为阳性对照，观察甘氨酸干预后胰岛素受体底物-1（IRS-1）和过氧化物酶体增殖物激活受体γ（PPARγ）基因的表达。结果:正常对照组脂肪细胞IRS-1mRNA和PPARγ mRNA的表达最强；TNF-α组IRS-1mRNA和PPARγ mRNA表达显著低于正常对照组；TNF-α加罗格列酮组与TNF-α加甘氨酸组相似，IRS-1mRNA和PPARγ mRNA表达显著高于TNF-α组。结论:甘氨酸对TNF-α诱导的3T3-L1脂肪细胞胰岛素抵抗具有抑制作用，其机制与其增强IRS-1、PPARγ基因的表达有关。     

GH与EGFR受体后信号交联在GH促进青春期大鼠生长板软骨细胞增殖中的作用

目的: 观察促性腺激素释放激素类似物(GnRHa)处理后青春期大鼠生长板体外培养的软骨细胞内是否存在生长激素(GH)与表皮生长因子受体(EGFR)之间的信号交联(cross-talk)。方法: 3周龄雌性SD大鼠开始注射GnRHa至7周龄;随后分离培养5-8只大鼠胫骨生长板软骨细胞,在GH作用前分别加入JAK2阻断剂AG490(1 nmol/L、10 nmol/L和100 nmol/L)、EGFR酪氨酸激酶阻断剂AG1478(0.1 nmol/L、1 nmol/L和10 nmol/L)和表皮生长因子(EGF)中和抗体(0.1 mg/L、1 mg/L和10 mg/L);采用四氮甲基唑蓝(MTT)以及免疫组化法测定增殖细胞核抗原(PCNA),观察不同阻断剂对软骨细胞增殖的影响;采用Western blotting检测软骨细胞p-ERK1/2及p-EGFR的表达。结果: GH作用后具有浓度依赖性地促进软骨细胞增殖和增加p-ERK1/2及p-EGFR水平的作用,100 μg/L时作用最为明显。AG490及AG1478几乎能完全抑制GH促进软骨细胞增殖和激活ERK1/2及EGFR的作用。 而EGF中和抗体仅能部分抑制GH的作用。结论: GH通过激活JAK2而激活其下游的ERK通路,实现其直接促细胞增殖效应。GH亦能通过激活EGFR及其信号转导通路促进细胞增殖效应,表明GH通路和EGF通路间存在相互作用。     

JAK2抑制剂对食管癌细胞增殖、凋亡及COX-2表达的影响

目的 研究食管癌细胞Eca-109增殖、凋亡及COX-2表达与信号转导子和激活子3（STAT3）信号传导通路的关系，明确以JAK2/STAT3为靶向的信号转导在Eca-109细胞中的分子调控机制。方法 将JAK2抑制剂AG490作用于Eca-109细胞，用MTT法检测细胞增殖；流式细胞仪、DNA琼脂糖电泳法及透射电子显微镜检测细胞凋亡；Western blot法检测细胞中JAK2、p-JAK2、p-Stat3及COX-2的蛋白表达变化；RT-PCR 检测COX-2 mRNA的变化。结果 AG490呈时间、剂量依赖性的抑制Eca-109细胞增殖并诱导凋亡，抑制JAK2/STAT3通路蛋白的表达，呈浓度依赖性地下调p-JAK2及p-Stat3蛋白的表达（P <0.05），并下调COX-2 mRNA及蛋白的表达（P <0.05）。结论 JAK2/STAT3信号传导通路调控AG490对Eca-109细胞作用的细胞内信号传导机制，最终通过下调COX-2表达影响Eca-109细胞的增殖并诱导凋亡。     

罗格列酮对多囊卵巢综合征患者卵巢黄素化颗粒细胞胰岛素受体底物1和2蛋白表达及酪氨酸磷酸化的影响

目的： 研究罗格列酮对多囊卵巢综合征(PCOS)患者卵巢黄素化颗粒细胞胰岛素受体底物-1(IRS-1)和IRS-2蛋白表达及酪氨酸磷酸化的影响。探讨罗格列酮改善PCOS卵巢局部胰岛素抵抗的作用。方法: 收集行IVF-ET治疗的11例PCOS患者（PCOS组）和15例排卵正常患输卵管性不孕患者（对照组）促排卵后黄素化颗粒细胞行体外培养，分别用不同浓度罗格列酮（0、1、10、100、1 000、10 000 nmol/L）处理细胞48 h，采用RT-PCR、免疫印迹（Western blotting）及免疫沉淀法分别检测卵巢黄素化颗粒细胞IRS-1和IRS-2mRNA的表达、蛋白含量及酪氨酸磷酸化水平。结果: （1）与对照比较，PCOS组黄素化颗粒细胞IRS-1mRNA表达及蛋白含量显著增加（P<0.05），IRS-2mRNA表达及蛋白含量显著降低（P<0.05），IRS-1和IRS-2酪氨酸磷酸化水平均显著降低（P<0.05，P<0.05）；（2）不同浓度罗格列酮作用后，PCOS组黄素化颗粒细胞IRS-1mRNA及蛋白表达显著降低，IRS-2mRNA及蛋白表达显著增加，同时IRS-1和IRS-2酪氨酸磷酸化水平也显著增加，而正常对照组黄素化颗粒细胞IRS表达及酪氨酸磷酸化水平无显著变化。结论: PCOS患者卵巢局部存在胰岛素抵抗，其原因可能与IRS-1和IRS-2蛋白表达及酪氨酸磷酸化异常有关；罗格列酮可以通过调整IRS-1和IRS-2表达失衡，提高IRS-1和IRS-2酪氨酸磷酸化水平，改善PCOS患者卵巢局部胰岛素抵抗。     

骨痨愈康丸通过JAK/STAT信号通路对类风湿关节炎大鼠滑膜组织的影响

目的：观察骨痨愈康丸（GLYK）对胶原诱导性关节炎（CIA）大鼠滑膜组织的影响,探讨GLYK治疗类风湿关节炎的作用机制。方法：将70只Wistar大鼠,随机分为正常对照（control）组、CIA组、甲氨蝶呤（MTX）组、GLYK组、GLYK+Janus激酶（JAK）受体酪氨酸激酶抑制剂AG490(GLYK+AG490)组和AG490组。除control组外,其余5组建立CIA大鼠模型,每组10只。用药4周后,观察各组大鼠踝关节病理形态;ELISA法检测关节液中白细胞介素6(IL-6)、IL-17、IL-1β、肿瘤坏死因子α(TNF-α)和基质金属蛋白酶3(MMP-3)水平;RT-qPCR与Western blot检测各组大鼠踝关节滑膜组织中JAK2、JAK3、信号转导和转录激活因子3(STAT3)、细胞因子信号抑制因子1(SOCS1)和SOCS3的mRNA及蛋白表达。结果：CIA组大鼠关节液中IL-6、IL-17、IL-1β、TNF-α和MMP-3的水平、滑膜组织中JAK2、JAK3和STAT3蛋白及相关mRNA的表达较control组显著升高（P<0.01）,SOCS1和SO...     

自发性2型糖尿病大鼠主动脉形态学改变与胰岛素受体底物1mRNA的表达

目的研究自发性2型糖尿病OLETF大鼠在疾病发展的不同阶段，其主动脉组织形态学改变以及胰岛素受体底物-1（IRS-1）mRNA的表达水平，探讨胰岛素抵抗状态下大血管病变的发生机制。方法10只OLETF大鼠随机分别在16周龄与24周龄检杀，10只同种系非糖尿病LETO大鼠为正常对照组。应用光镜和透射电镜观察大鼠主动脉组织形态学改变，原位杂交技术检测主动脉IRS-1 mRNA表达。结果OLETF大鼠在16周龄时主动脉已出现超微结构异常，至24周时其病变程度加重，表现为典型动脉粥样硬化性早期改变；OLETF大鼠在16周和24周时其主动脉IRS-1 mRNA的表达均明显低于同期LETO对照组，分别减少24．6％（P〈0．01）和25．6％（P〈0．001）。结论血管组织胰岛素受体后信号传递分子在基因转录水平即存在异常，导致内皮细胞胰岛素抵抗，可能是糖尿病早期大血管病变危险性增加的机制之一。     

宫内发育迟缓大鼠胰腺肝脏骨骼肌中胰岛素受体底物的表达

目的分析宫内发育迟缓（IUGR）大鼠胰腺、肝脏、骨骼肌中胰岛素受体底物1（IRS-1）和2（IRS-2）mRNA和蛋白水平的表达,探讨IUGR个体发生胰岛素抵抗的机制。方法采用母孕期低蛋白饮食法建立IUGR大鼠模型,以模型鼠产下的仔鼠为IUGR组;以孕期予正常饮食母鼠产下的仔鼠为对照组。应用RT-PCR法检测各组仔鼠在出生后0、3和8周时点胰腺、肝脏和骨骼肌中IRS-1、IRS-2 mRNA表达水平,采用Western blot检测IRS-1和IRS-2蛋白表达水平。检测3和8周时点仔鼠空腹血糖和血清胰岛素水平,计算胰岛素抵抗指数。结果①IUGR组出生后0和3周体重显著低于对照组;8周时点IUGR组体重显著高于对照组。②IUGR组出生后0、3和8周时点胰腺、肝脏IRS-2 mRNA和蛋白表达水平低于对照组;IRS-1 mRNA和蛋白表达水平与对照组差异无统计学意义;骨骼肌IRS-1 mRNA和蛋白表达水平均显著低于对照组;IRS-2蛋白表达水平与对照组差异无统计学意义。③至8周时点,骨骼肌IRS-1 mRNA和蛋白表达水平的下降幅度较胰腺和肝脏组织更为明显;肝脏IRS-2 mRNA和蛋白表达水平的下降幅度较胰腺和骨骼肌组织更为明显。④至8周时点,IUGR组空腹血糖水平与对照组差异无统计学意义,胰岛素水平和空腹胰岛素抵抗指数较对照组显著升高。结论 IUGR大鼠胰腺、肝脏和骨骼肌组织均存在IRS-1或IRS-2 mRNA和蛋白表达水平的下降,可能是发生胰岛素抵抗的机制之一。     

γ-干扰素通过激活JAK/STAT信号转导途径上调小鼠系膜细胞内HMGB1表达

目的:本实验以小鼠系膜细胞为研究对象,IFN-γ为刺激物,通过检测JAK/STAT信号途经的激活及HMGB1mRNA及蛋白表达,探讨γ干扰素刺激系膜细胞HMGB1表达上调的可能机制。方法:常规培养小鼠系膜细胞(Mousemesangial cell,MMC),无血清培养基同步化后分为正常对照组、IFN-γ(500 U/ml)刺激组和INF-γ+AG490(INF-γ500 U/ml+AG490 200μmol/ml)组。Western blot检测JAK、STAT1和HMGB1蛋白的表达变化,RT-PCR检测HMGB1mRNA的表达变化。结果:Western blot结果显示IFN-γ能够促进小鼠系膜细胞JAK、STAT1磷酸化和STAT1核转位,并呈时间依赖性;AG490能够降低IFN-γ介导的JAK1、JAK2、STAT1的活化,并呈时间依赖性。IFN-γ能够上调系膜细胞中HMGB1mRNA及蛋白表达,并随着刺激时间延长,其相对表达量呈上升趋势,AG490处理后,系膜细胞中HMGB1mRNA蛋白表达降低,并随时间延长而下调。结论:IFN-γ能够促进小鼠系膜细胞HMGB1表达上调,JAK/STAT信号通路激活可能是其主要机制之一。     

丝胶对2型糖尿病大鼠胰腺胰岛素PI3K-Akt信号通路的调节作用

目的探讨丝胶是否通过影响胰腺胰岛素PI3K-Akt信号通路发挥降血糖的作用。方法 36只雄性SD大鼠随机分为正常对照组、糖尿病模型组和丝胶治疗组,每组12只。采用高脂高糖饲料喂养联合链脲佐菌素(35mg/kg,2次,1次/d)连续腹腔注射法制作2型糖尿病大鼠模型,模型成功标准是空腹血糖≥11.1mmol/L。模型成功建立后,丝胶治疗组大鼠给予丝胶灌胃35d。采用ELISA法检测大鼠血清脂联素水平,Western blotting法和Real-time PCR法分别检测大鼠胰腺胰岛素受体(IR)、胰岛素受体底物-1(IRS-1)、磷脂酰肌醇-3-激酶(PI3K)和Akt蛋白和mRNA的表达情况。结果与糖尿病模型组比较,丝胶治疗组大鼠血清脂联素水平,胰腺IR、IRS-1、PI3K、Akt蛋白和mRNA的表达明显升高(P0.01,P0.05)。结论丝胶可通过上调糖尿病模型大鼠胰腺IR、IRS-1、PI3K和Akt的表达,改善糖尿病时胰腺胰岛素PI3K-Akt信号转导通路的异常,从而发挥降低血糖的作用。     

The effect of aging on insulin signalling pathway is tissue dependent: Central role of adipose tissue in the insulin resistance of aging

Insulin resistance progressively increases with age, resulting in excessively high incidence of T2D in the elderly population. To investigate the molecular mechanisms underlying insulin resistance of aging, we carried out a comparative study of insulin signalling cascade in adipose tissue, liver and skeletal muscle. We measured the protein levels in different subcellular compartments and the phosphorylation status of key components of the insulin signalling pathway in response to in vivo insulin infusion. White adipose tissue (WAT) from old rats shows altered subcellular distribution of insulin receptor (IR) and insulin receptor substrate 1 (IRS-1) and a marked reduction in the insulin-stimulated IR tyrosine phosphorylation. Furthermore, activation of Akt, as well as GLUT4 translocation to the plasma membrane, is impaired. Quadriceps muscle from old rats also has a defect in GLUT4 trafficking but, in contrast to WAT, insulin signalling at the level of IR and Akt is increased. In liver, we found no major differences in the ability of insulin to induce autophosphorylation of the IR or activation of Akt between adult and old animals. These data, therefore, show at the molecular level that insulin resistance in adipose tissue precedes the development of liver and muscle insulin resistance in aged rats.     

β3-Adrenergic-dependent and -independent mechanisms participate in cold-induced modulation of insulin signal transduction in brown adipose tissue of rats

During cold exposure, homeothermic animals mobilize glucose with higher efficiency than at thermoneutrality. An interaction between the insulin signal transduction machinery and high sympathetic tonus is thought to play an important role in this phenomenon. In the present study, rats were exposed to cold during 8 days and treated, or not, with a 3-adrenergic agonist, BRL37344 sodium 4-2-2-(3-chlorophenyl)-2-hydroxyethyl amino propyl phenoxy-acetic acid sodium (BRL37344), or antagonist, SR59230A 3-(2-ethylphenoxy)-[(1S)-1,2,3,4-tetrahydronaphth-1-ylamino]-(2S)-2-propanol oxalate (SR59230A), to evaluate the cross-talk between insulin and 3-adrenergic intracellular signaling in brown adipose tissue. The drugs did not modify food ingestion, body temperature, and body weight in control and cold-exposed rats. Treatment of control rats with BRL37344 led to higher insulin-induced tyrosine phosphorylation of the insulin receptors, insulin receptor substrate (IRS)-1 and ERK, higher insulin-induced IRS-1/PI3-kinase association, and higher [Ser⁴⁷³] phosphorylation of Akt. Cold exposure alone promoted higher insulin-induced tyrosine phosphorylation of the insulin receptors, IRS-1, IRS-2, and ERK, and higher insulin-induced IRS-1 and IRS-2/PI3-kinase association. Except for the regulation of ERK, SR59230A abolished all the cold-induced effects upon the insulin signal transduction pathway. However, this antagonist only partially inhibited the cold-induced increase of glucose uptake. Thus, the sympathetic tonus generated during cold-exposure acts, in brown adipose tissue, through the 3-adrenergic receptor and modulates insulin signal transduction, with the exception of ERK. However, insulin-independent mechanisms other than 3-adrenergic activation participate in cold-induced glucose uptake in brown adipose tissue of rats.     

Beneficial effects of Ginkgo biloba extract on insulin signaling cascade,dyslipidemia, and body adiposity of diet-induced obese rats

Ginkgo biloba extract (GbE) has been indicated as an efficient medicine for the treatment of diabetes mellitus type 2. It remains unclear if its effects are due to an improvement of the insulin signaling cascade, especially in obese subjects. The aim of the present study was to evaluate the effect of GbE on insulin tolerance, food intake, body adiposity, lipid profile, fasting insulin, and muscle levels of insulin receptor substrate 1 (IRS-1), protein tyrosine phosphatase 1B (PTP-1B), and protein kinase B (Akt), as well as Akt phosphorylation, in diet-induced obese rats. Rats were fed with a high-fat diet (HFD) or a normal fat diet (NFD) for 8 weeks. After that, the HFD group was divided into two groups: rats gavaged with a saline vehicle (HFD+V), and rats gavaged with 500 mg/kg of GbE diluted in the saline vehicle (HFD+Gb). NFD rats were gavaged with the saline vehicle only. At the end of the treatment, the rats were anesthetized, insulin was injected into the portal vein, and after 90s, the gastrocnemius muscle was removed. The quantification of IRS-1, Akt, and Akt phosphorylation was performed using Western blotting. Serum levels of fasting insulin and glucose, triacylglycerols and total cholesterol, and LDL and HDL fractions were measured. An insulin tolerance test was also performed. Ingestion of a hyperlipidic diet promoted loss of insulin sensitivity and also resulted in a significant increase in body adiposity, plasma triacylglycerol, and glucose levels. In addition, GbE treatment significantly reduced food intake and body adiposity while it protected against hyperglycemia and dyslipidemia in diet-induced obesity rats. It also enhanced insulin sensitivity in comparison to HFD+V rats, while it restored insulin-induced Akt phosphorylation, increased IRS-1, and reduced PTP-1B levels in gastrocnemius muscle. The present findings suggest that G. biloba might be efficient in preventing and treating obesity-induced insulin signaling impairment.     

厄贝沙坦对高血压合并2型糖尿病大鼠胰岛素抵抗IRS-1/PI3K/GLUT4信号通路的影响

目的　探讨厄贝沙坦对高血压合并2型糖尿病（T2DM）大鼠胰岛素抵抗的影响及其作用。 方法　自发性高血压大鼠（SHR）采用高糖高脂饮食联合链脲佐菌素（STZ）建立T2DM模型,随机分为模型组、厄贝沙坦低、高剂量组。以正常大鼠作为对照组。厄贝沙坦低、高剂量组每日分别按30、60 mg/kg剂量灌服厄贝沙坦,对照组和模型组灌服等量生理盐水。测量大鼠收缩压（SBP）、空腹血糖（FBG）、胰岛素抵抗模型评估指数（HOMA-IR）、胰岛素受体底物-1（IRS-1）、磷脂酰肌醇（-3）激酶p85亚基（PI3Kp85）、蛋白激酶B（AKT）、磷酸化蛋白（p-AKT）及葡萄糖转运蛋白4（GLUT4）的表达。 结果　与对照组相比,模型组SBP、FBG、FINS和HOMA-IR升高（P<0.05）,IRS-1、PI3Kp85、p-AKT和GLUT4降低（P<0.05）;与模型组相比,厄贝沙坦低、高剂量上述指标均发生逆转（P<0.05）。 结论　厄贝沙坦可通过IRS-1/PI3K/GLUT4信号通路改善高血压合并T2DM大鼠胰岛素抵抗。     

Implications for the insulin signaling pathway in Snell dwarf mouse longevity: a similarity with the C. elegans longevity paradigm

Mutation analyses in the nematode, Caenorhabditis elegans, and mice have identified genes that increase their life-span via hormonal signal transduction, i.e. the insulin/insulin-like growth factor-1 (IGF-1) pathway in nematodes, and the growth hormone (GH)-thyriod stimulating hormone (TSH)-prolactin system in Snell dwarf mouse mutants. We have shown that the GH deficiency due to Pit1 mutation in the long-lived Snell dwarf mice may decrease circulating insulin levels, thereby resulting in a decreased activity of the insulin/IGF-1 signaling pathway. The data presented are consistent with our hypothesis that the decreased circulating insulin levels resulting from the Pit1 mutation mimics a physiological state similar to that proposed to occur in the long-lived C. elegans, daf-2 mutant. Our studies demonstrate a series of changes in components of the insulin/IGF-1-signaling pathway that suggest a reduction-of-function of this pathway in the aged dwarf. These include a decreased IRS-2 pool level, a decrease in PI3K activity and its association with IRS-2 and decreased docking of p85alpha to IRS-2. Our data also suggest a preferential docking of IRS-2-p85 alpha -p110 alpha in the aged dwarf liver and IRS-2-p85 alpha -p110 beta in the aged control. We speculate that the preference for the p110 alpha-containing complex may be a specific characteristic of a downstream segment of the longevity-signaling cascade. We conclude that the Pit1 mutation may result in physiological homeostasis that favors longevity, and that the Snell dwarf mutant conforms to the nematode longevity paradigm.     

脂肪细胞在肝细胞胰岛素耐受过程中的作用

目的研究脂肪细胞在不同分化阶段对肝细胞胰岛素抵抗的影响。方法体外诱导3T3-L1脂肪前体细胞分化,细胞内脂滴增加,逐步分化成脂肪细胞。采用不同分化阶段脂肪细胞(未分化0d、中期分化4d、接近完全分化8d)与原代肝细胞共培养。Western印迹法检测共培养后肝细胞内胰岛素信号通路的反应性;葡萄糖同位素标记方法检测肝细胞糖原合成能力。结果以未共培养的肝细胞为对照组,共培养后肝细胞内胰岛素受体底物-2酪氨酸磷酸化(Tyr612)(pIRS-2)水平及Akt磷酸化(Ser473)(pAkt)水平均显著下调;肝糖原合成能力明显降低;与较成熟脂肪细胞共培养后,肝细胞pIRS-2及pAkt水平与其他分化阶段组共培养比较下调明显,肝糖原合成能力随着脂肪细胞的成熟而明显降低。结论脂肪细胞可能诱导肝细胞发生胰岛素抵抗,肝细胞胰岛素信号通路的阻滞程度与脂肪细胞的分化程度呈正相关。