石榴花多酚对糖尿病大鼠IL-6、TXB2及PPAR-γ mRNA基因表达的影响

目的观察石榴花多酚对小剂量链脲佐菌素加高脂饲料诱导的胰岛素抵抗模型大鼠IL-6、TXB2以及心肌组织PPAR-γ mRNA基因表达的影响。方法♂SD大鼠高脂饲料喂养1mon后注射小剂量STZ,2wk后测大鼠空腹血糖,血糖值>11.1者为造模成功的大鼠,将造模成功的大鼠随机分为模型组和药物干预组,另设空白对照组,药物干预1mon,常规测定各组大鼠给药前后的空腹血糖(FPG)和给药后各组大鼠的空腹血清胰岛素水平(Fins)、IL-6、TXB2,计算胰岛素敏感性指数(ISI)、胰岛素抵抗指数(Homa-IRI),提取心肌组织总RNA,采用逆转录PCR技术扩增PPAR-γ基因片段,检测其基因表达水平。结果石榴花多酚能降低模型大鼠FPG水平和Fins、IL-6、TXB2含量,增加PPAR-γmRNA基因表达,提高ISI,降低Homa-IRI。结论石榴花多酚对大鼠IR有一定程度的改善作用,其机制可能与提高IR大鼠心肌组织PPAR-γ基因的表达有关。     

丁香等中药对2型糖尿病大鼠糖代谢的影响

目的:观察丁香、桂皮对2型糖尿病糖代谢的影响并探讨其机制。方法:采用小剂量链脲佐菌素静脉注射并通过喂饲高热量饮食建立类似人类2型糖尿病的大鼠模型,用丁香、桂皮液干预治疗,检测干预前后血糖、血胰岛素、肝糖原、肌糖原及肝葡萄糖激酶水平。结果:丁香对2型糖尿病大鼠的的糖耐量异常无显著性影响(P>0.05),相反可使大鼠肝糖原、肌糖原储量显著降低;而桂皮则可显著改善2型糖尿病大鼠的糖耐量异常,显著增加大鼠肝糖原、肌糖原储量,增强其葡萄糖激酶活性(P<0.05)。结论:丁香可使2型糖尿病大鼠肝糖原、肌糖原储量减少。桂皮增强2型糖尿病大鼠肝葡萄糖激酶活性、增加其肝糖原、肌糖原储存量,可能是改善其糖代谢的重要环节。     

去胸腺对大鼠糖代谢的影响及地黄寡糖对其的调节作用

目的　观察去胸腺 (Tx)大鼠血糖、血浆胰岛素水平及肝糖原的变化及地黄寡糖 (ROS)对去胸腺大鼠糖代谢的调节作用。方法　① 4wk龄Wistar大鼠手术摘除胸腺 ,测定大鼠去胸腺 3、4、8、15mon后血浆葡萄糖、肝糖原含量、血浆胰岛素水平 ;②观察ROS(2 5 0mg·kg-1,po,× 6 0d)给予去胸腺术 7月后对大鼠脾淋巴细胞增殖、血糖、肝糖原、血浆胰岛素及皮质酮水平的影响。结果　①大鼠去胸腺术后 3～ 15mon血糖无明显变化 ,但从 8mon起肝糖原含量及胰岛素水平均升高 ;②ROS可基本逆转去胸腺大鼠糖代谢变化 ,使之向正常发展 :使肝糖原由高向正常转化 ;血浆胰岛素水平在Tx大鼠有升高趋势 ,ROS可使之恢复正常 ;血浆皮质酮水平在Tx大鼠有下降 ,ROS可使之恢复上升 ;ROS可逆转因去胸腺引起之脾淋巴细胞增殖下降。结论　大鼠去胸腺可引起糖代谢的某些变化 ,ROS可以大部分逆转这种变化     

2型糖尿病血清游离脂肪酸、血糖、血脂水平及其关系的分析

游离脂肪酸(FFA)水平的升高,在2型糖尿病糖代谢异常的发生、发展中起了十分重要的作用,同时,血中游离脂肪酸的改变一定程度上反映了体内脂代谢的状况。本文对72例2型糖尿病和32例正常人进行血清FFA、空腹血糖(FPG)、空腹胰岛素     

葛根素增强2型糖尿病-胰岛素抵抗大鼠胰岛素敏感性和抗氧化作用

目的观察葛根素对2型糖尿病-胰岛素抵抗大鼠胰岛素敏感性及血糖、血脂和氧化应激作用。方法采用腹腔注射(ip)小剂量链脲霉素(25-30mg?kg-17d-1,qd×1d),并加饲高热量饮食(富含脂肪和蔗糖)42d,造成糖耐量减退(IGT)、IR的T2DM大鼠模型;灌胃给药(ig)葛根素0．3g?kg-1、0．15g?kg-1或二甲双胍0．25g?kg- 1,qd×28d;测病鼠空腹血糖(FBG)和口服葡萄糖耐量试验(OGTT)后2小时血糖(2hBG)以及空腹血清血糖(FSG)、三酰甘油(TG)、游离脂肪酸(FFA)、总胆固醇(TC)、低密度脂蛋白-胆固醇(LDL-C)、高密度脂蛋白-胆固醇(HDL-C)、糖化血红蛋白(GHb)、果糖胺(FRA)、丙二醛(MDA)和胰岛素(FIns)含量及超氧化物歧化酶(SOD)活性,计算胰岛素敏感指数(ISI)和胰岛素抵抗指数(IRI)。结果葛根素和二甲双胍均能显著降低病鼠Fins和IRI,而提高ISI(P<0．01),增强胰岛素敏感性;降低FBG和OGTT。后2hBG,以及TC,LDL-C,HDL-C,TG和FFA含量(P<0．01),改善糖脂代谢紊乱;降低MDA含量和提高SOD活性(P<0．01),增强清除自由基能力。结论葛根素对T2DM大鼠能产生二甲双胍样的改善高胰岛素血症、提高胰岛素敏感性以及降糖和降血脂等效应,并具有抗氧化活性。     

白细胞介素6对2型糖尿病大鼠骨骼肌糖代谢的影响

目的：通过研究白细胞介素6（IL－6）对2型糖尿病（T2DM）大鼠骨骼肌葡萄糖转运体4（GLUT4）和糖原含量的影响,探讨其影响T2DM糖代谢的机制。方法：健康雄性SD大鼠随机分为4组：正常对照组（N组）10只,糖尿病IL-6抗原干预组（A组）10只,糖尿病IL－6抗体干预组（B组）8只,糖尿病对照组（C组）8只。测定血糖、血清胰岛素、血脂等指标;取股四头肌比色法测定肌糖原含量,免疫组化法测定骨骼肌GLUT4蛋白表达。结果：T2DM大鼠骨骼肌糖原含量和GLUT4蛋白表达较正常大鼠明显降低,IL-6抗体干预可以升高T2DM大鼠骨骼肌糖原含量和GLUT4蛋白表达。结论：T2DM大鼠骨骼肌GLUT4蛋白表达减少;IL－6抗体阻滞通过增加GLUT4蛋白表达促进骨骼肌对糖的利用。     

齐墩果酸对糖尿病大鼠糖耐量及肝糖原的影响

目的研究齐墩果酸对糖尿病大鼠糖耐量及肝糖原的影响,以期进一步研究齐墩果酸降血糖的作用机制。方法随机取10只大鼠作为正常组,其余40只大鼠采用链脲菌素复制糖尿病大鼠模型,造模成功后,按血糖值分为5组,每组10只,模型组、齐墩果酸高(100mg.kg-1)、低剂量组(50mg.kg-1)、二甲双胍组,测定糖耐量;连续给药30天后,测定空腹血糖和肝糖原含量。结果齐墩果酸对糖尿病大鼠具有明显改善糖耐量,降低空腹血糖及增加肝糖原的作用。结论齐墩果酸改善糖耐量可能与抑制糖苷酶活性有关,而增加肝糖原与促进肝糖原合成,同时减少糖异生有一定的关系。     

金钗石斛生物总碱对糖尿病大鼠血糖及肝脏脂肪变性的影响

目的研究金钗石斛生物总碱(DNLA)对糖尿病大鼠血糖及肝脏脂肪变性的影响。方法雄性SD大鼠高脂、高糖饲料喂养大鼠6周后,一次腹腔注射链脲佐菌素40 mg.kg-1诱导糖尿病大鼠模型。糖尿病大鼠随机分为模型组,二甲双胍组(二甲双胍100 mg.kg-1)和DNLA 20、40、80 mg.kg-1组,每组11只。另取基础饲料喂养SD大鼠10只设为正常对照组。给药组每日灌胃给药1次,连续4周,正常对照组及模型组给予等体积的双蒸水灌胃。检测大鼠空腹血糖(FPG)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)、游离脂肪酸(FFA)、三酰甘油(TG)、总胆固醇(TC)水平,观察肝脏病理形态变化。结果与正常对照组比较,模型组大鼠FPG、FINS、HOMA-IR、FFA、TG均明显升高(P<0.05),肝脏组织发生脂肪变性。二甲双胍组,DNLA 40、80 mg.kg-1组大鼠的FPG、FINS、HOMA-IR低于模型组(P<0.05),DNLA 80 mg.kg-1组FPG、FINS、HOMA-IR水平与二甲双胍组无显著差异(P>0.05)。DNLA 40、80 mg.kg-1组FFA低于模型组(P<0.05),二甲双胍组与模型组相比无显著差异(P>0.05)。DNLA 20、40、80 mg.kg-1组和二甲双胍组TG水平与模型组相比无显著差异(P>0.05)。DNLA 40、80 mg.kg-1组大鼠肝脏脂肪变性程度减轻。结论 DNLA可降低糖尿病大鼠血糖,减轻肝脏脂肪变性,其机制可能与改善胰岛素抵抗有关。     

柚皮苷对实验性2型糖尿病大鼠的作用研究

目的:研究柚皮苷对实验性2型糖尿病(T2DM)大鼠的药理作用.方法:通过给予大鼠高脂饲料结合小剂量链脲菌素(30 mg·kg-1)制备T2DM模型.动物分为正常对照组、模型组、阳性对照组、柚皮苷高剂量组(400 mg·kg-1)和低剂量组(200 mg·kg-1),连续给药20 d,测定空腹血糖,糖耐量,空腹胰岛素、血脂、肝脏MDA含量及SOD的活力.结果:与糖尿病模型组比较,柚皮苷两剂量组的空腹血糖,空腹胰岛素,总胆固醇,三酰甘油和肝脏MDA含量均显著降低(P<0.05);体重减少得到缓解;肝脏SOD的活力显著提高(P<0.01).结论:柚皮苷可以纠正T2DM大鼠的糖代谢和脂质代谢紊乱,减轻胰岛素抵抗,增强机体抗氧化能力,对肝脏起到保护作用.     

五环三萜抑制A549细胞生长与促进糖原累积作用的相关性研究

目的:研究五环三萜化合物(齐墩果酸和山楂酸)对人肺腺癌A549细胞的生长是否有抑制作用并对其可能的作用机制即抑制糖原磷酸化酶进行探讨。方法:用MTT法测定不同浓度的化合物对A549细胞生长的抑制作用;通过测定细胞中的糖原含量的变化证实化合物抑制了细胞中糖原磷酸化酶的活性。结果:MTT法测得化合物对A549细胞生长具有抑制作用。同时,测得齐墩果酸和山楂酸对A549细胞的糖原磷酸化酶具有抑制活性,其IC50分别是5.98和4.01μmol.L-1。进一步经化合物处理后的细胞内糖原含量呈现剂量依赖性增加。结论:齐墩果酸和山楂酸具有抑制A549细胞生长的作用,其作用可能是通过抑制细胞内的糖原磷酸化酶活性而实现的。     

Glutathione-dependent reduction of arsenate by glycogen phosphorylase responsiveness to endogenous and xenobiotic inhibitors.

Rabbit muscle glycogen phosphorylase-a (GPa) reduces arsenate (As(V)) to the more toxic arsenite (As(III)) in a glutathione (GSH)-dependent fashion. To determine whether reduction of As(V) by GPa is countered by compounds known to inhibit GP-catalyzed glycogenolysis, the effects of thiol reagents, endogenous compounds (glucose, ATP, ADP) as well as nonspecific glycogen phosphorylase inhibitors (GPIs; caffeine, quercetin, flavopiridol [FP]), and specific GPIs (1,4-dideoxy-1,4-imino-D-arabinitol [DAB], BAY U6751, CP320626) were tested on reduction of As(V) by rabbit muscle GPa in the presence of glycogen (substrate), AMP (activator), and GSH, and the As(III) formed from As(V) was quantified by high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry. The As(V)-reducing activity of GPa was moderately sensitive to thiol reagents. Glucose above 5mM and ADP or ATP at physiological levels diminished GPa-catalyzed As(V) reduction. All GPIs inhibited As(V) reduction by GPa in a concentration-dependent fashion; however, their effects were differentially affected by glucose (10mM) or AMP (200microM instead of 25microM), known modulators of the action of some GPIs on the GP-catalyzed glycogenolysis. Inhibition of As(V) reduction by DAB and quercetin was not influenced by glucose or AMP. Glucose that potentiates the inhibitory effects of caffeine, BAY U6751, and CP320626 on the glycogenolytic activity of GPa also enhanced the inhibitory effects of these GPIs on GPa-catalyzed As(V) reduction. AMP at high concentration alleviated the inhibition by BAY U6751 and CP320626 (whose antagonistic effect on GP-catalyzed glycogen breakdown is also AMP sensitive), whereas the inhibition in As(V) reduction by FP or caffeine was little affected by AMP. Thus, GPIs inhibit both the glycogenolytic and As(V)-reducing activities of GP, supporting that the latter is coupled to glycogenolysis. It was also shown that a GPa-rich extract of rat liver contained GSH-dependent As(V)-reducing activity that was inhibited by specific GPIs, suggesting that the liver-type GPa can also catalyze reduction of As(V).     

牡蛎不同提取方法中糖原含量的比较

目的 通过含量测定,筛选适宜的牡蛎糖原提取方法。方法采用比色法,以苯酚-硫酸溶液为显色体系,检测波长为490nm。结果葡萄糖进样量线性范围为10～80μg（r=0．9988）,平均回收率97．74％,RSD=0．91％（n=6）。水提法获得的样品糖原含量最高,为48．46％;经Sephadex G-50凝胶柱层析收集第Ⅱ峰,其冻干品的糖原平均含量为26．12％。结论比色法方法简便、准确、重现性好,可用于牡蛎中糖原含量测定：     

Glutathione-dependent reduction of arsenate by glycogen phosphorylase a reaction coupled to glycogenolysis.

Arsenate (As(V)) is reduced in the body to the more toxic arsenite (As(III)). We have shown that two enzymes catalyzing phosphorolytic cleavage of their substrates, namely purine nucleoside phosphorylase and glyceraldehyde-3-phosphate dehydrogenase, can reduce As(V) in presence of an appropriate thiol and their substrates. Another phosphorolytic enzyme that may also reduce As(V) is glycogen phosphorylase (GP). With inorganic phosphate (P(i)), GP catalyzes the breakdown of glycogen to glucose-1-phosphate; however, it also accepts As(V). Testing the hypothesis that GP can reduce As(V), we incubated As(V) with the phosphorylated GPa or the dephosphorylated GPb purified from rabbit muscle and quantified the As(III) formed from As(V) by high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry. In the presence of adenosine monophosphate (AMP), glycogen, and glutathione (GSH), both GP forms reduced As(V) at rates increasing with enzyme and As(V) concentrations. The As(V) reductase activity of GPa was 10-fold higher than that of GPb. However, incubating GPb with GP kinase and ATP (that converts GPb to GPa) increased As(V) reduction by phosphorylase up to the rate produced by GPa incubated under the same conditions. High concentration of inorganic sulfate, which activates GPb like phosphorylation, also promoted reduction of As(V) by GPb. As(V) reduction by GPa (like As(V) reduction in rats) required GSH. It also required glycogen (substrate for GP) and was stimulated by AMP (allosteric activator of GP) even at low micromolar concentrations. P(i), substrate for GP competing with As(V), inhibited As(III) formation moderately at physiological concentrations. Glucose-1-phosphate, the product of GP-catalyzed glycogenolysis, also decreased As(V) reduction. Summarizing, GP is the third phosphorolytic enzyme identified capable of reducing As(V) in vitro. For reducing As(V) by GP, GSH and glycogen are indispensable, suggesting that the reduction is linked to glycogenolysis. While its in vivo significance remains to be tested, further characterization of the GP-catalyzed As(V) reduction is presented in the adjoining paper.     

Species differences in the hepatic and intestinal metabolism of cyclosporine

1. Cyclosporin A (cyclosporine, CSA) is an immunosuppressive drug with a narrow therapeutic index. In the present study the metabolism of CSA was investigated in the liver and small intestinal microsomes obtained from rat, hamster, rabbit, dog, baboon and man by measuring the disappearance of CSA and the formation of the principal metabolites of CSA, namely hydroxylated and N-demethylated CSA. 2. CSA was metabolized at a very slow rate (2-8% metabolism in 30 min) in rat liver microsomes whereas microsomes from dog livers were very efficient (70-100% metabolism in 30 min) in metabolizing CSA. Hydroxylation and N-demethylation accounted for most of the CSA metabolized in all the species tested. 3. Microsomes from the small intestine produced qualitatively a similar metabolic profile as compared with the microsomes from the liver, but at a slower rate in allthe species tested. The relative importance of the different metabolic pathways, however, differed between species. 4. This study pointsto the importance of recognizing the similarities andthe differences in the metabolism of CSA in different species when data from animal studies are extrapolated to man.     

糖尿病治疗新靶点糖原合成酶激酶-3抑制剂的研究进展

糖原合成酶激酶-3(glycogen synthase kinase-3，GSK-3)属丝氨酸/苏氨酸类激酶，最早是作为一种能磷酸化并抑制糖原合成酶活性的蛋白激酶而被发现的。已发现在某些人类疾病中GSK-3的活性异常升高，如糖尿病、阿尔茨海默病及其他一些神经退行性疾病。现已找到了一些小分子GSK-3抑制剂主要是通过使GSK-3的丝氨酸位点磷酸化，从而抑制其活性。GSK-3活性被抑制后，能影响胰岛素信号传导、葡萄糖代谢及糖原的合成。因此开发GSK-3抑制剂已成为研究抗糖尿病药物的一个新思路。本文主要介绍GSK-3与糖尿病的联系及近年来GSK-3抑制剂在抗糖尿病作用方面的研究进展。     

Assessing the toxicity of herbicide isoproturon on Aporrectodea caliginosa (Oligochaeta) and its fate in soil ecosystem

This study was conducted to determine the residues of isoproturon and its metabolites, 1-(4-isopropylphenyl)-3-methylurea, 1-(4-isopropylphenyl) urea, and 4-isopropylanilin in soil and mature earthworms under laboratory conditions. Mature earthworms (Aporrectodea caliginosa) were exposed for various durations (7, 15, 30, and 60 days) to soils contaminated with isoproturon concentrations (2, 4, 6, 8, and 10 mg kg(-1) soil). The decrease in isoproturon concentration in the soil was inversely correlated to it's initial concentration. The highest concentration detected for isoproturon in earthworms was observed during the first 15 days and decreased thereafter. Acute toxicity of isoproturon was investigated; total soluble protein content and glycogen of the worms were evaluated. Levels of these parameters were related to isoproturon concentration in soil and earthworms. No lethal effect of isoproturon was observed even at the concentration of 1200 mg kg(-1) soil after 60 days of exposure. A reduction of total soluble protein was observed in all treated worms (maximum 59.54%). This study suggests the use of the total soluble protein content and glycogen of earthworms as biomarkers of exposure to isoproturon.     

Effect of training on activation of extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase pathways in rat soleus muscle

1. The effect of a chronic programme of either low- or moderate-to-high-intensity treadmill running on the activation of the extracellular-signal regulated protein kinase (ERK1/2) and the p38 mitogen-activated protein kinase (MAPK) pathways was determined in rat muscle. 2. Sprague-Dawley rats were assigned to one of three groups: (i) sedentary (NT; n = 8); (ii) low-intensity training (8 m/min; LIT; n = 16); and (iii) moderate-to-high-intensity training (28 m/min; HIT; n = 16). The training regimens were planned so that animals covered the same distance and had similar glycogen utilization for both LIT and HIT exercise sessions. 3. A single bout of LIT or HIT following 8 weeks of training led to a twofold increase in the phosphorylation of ERK1/2 (P = 0.048) and a two- to threefold increase in p38 MAPK (P = 0.005). Extracellular signal-regulated kinase 1/2 phosphorylation in muscle sampled 48 h after the last exercise bout was similar to sedentary values, while p38 MAPK phosphorylation was 70-80% lower than sedentary. One bout of LIT or HIT increased total ERK1/2 and p38 MAPK expression, with the magnitude of this increase being independent of prior exercise intensity or duration. Extracellular signal- regulated kinase 1/2 expression was increased three- to fourfold in muscle sampled 48 h after the last exercise bout irrespective of the prior training programme (P = 0.027), but p38 MAPK expression was approximately 90% lower than sedentary values. 4. In conclusion, exercise-training of different intensities/ durations results in selective postexercise activation of intracellular signalling pathways, which may be one mechanism regulating specific adaptations induced by diverse training programmes.     

Effects of dichloroacetate on glycogen metabolism in B6C3F1 mice

Dichloroacetate (DCA) is a by-product of drinking water chlorination. Administration of DCA in drinking water results in accumulation of glycogen in the liver of B6C3F1 mice. To investigate the processes affecting liver glycogen accumulation, male B6C3F1 mice were administered DCA in drinking water at levels varying from 0.1 to 3 g/l for up to 8 weeks. Liver glycogen synthase (GS) and glycogen phosphorylase (GP) activities, liver glycogen content, serum glucose and insulin levels were analyzed. To determine whether effects were primary or attributable to increased glycogen synthesis, some mice were fasted and administered a glucose challenge (20 min before sacrifice). DCA treatments in drinking water caused glycogen accumulation in a dose-dependent manner. The DCA treatment in drinking water suppressed the activity ratio of GS measured in mice sacrificed at 9:00 AM, but not at 3:00 AM. However, net glycogen synthesis after glucose challenge was increased with DCA treatments for 1–2 weeks duration, but the effect was no longer observed at 8 weeks. Degradation of glycogen by fasting decreased progressively as the treatment period was increased, and no longer occurred at 8 weeks. A shift of the liver glycogen–iodine spectrum from DCA-treated mice was observed relative to that of control mice, suggesting a change in the physical form of glycogen. These data suggest that DCA-induced glycogen accumulation at high doses is related to decreases in the degradation rate. When DCA was administered by single intraperitoneal (i.p.) injection to naïve mice at doses of 2–200 mg/kg at the time of glucose challenge, a biphasic response was observed. Doses of 10–25 mg/kg increased both plasma glucose and insulin concentrations. In contrast, very high i.p. doses of DCA (>75 mg/kg) produced progressive decreases in serum glucose and glycogen deposition in the liver. Since the blood levels of DCA produced by these higher i.p. doses were significantly higher than observed with drinking water treatment, we conclude that apparent differences with data of previous investigations is related to substantial differences in systemic dose and/or dose–time relations.     

迷走神经对大鼠肝脏葡萄糖代谢和纤维化的影响

目的:研究迷走神经对于大鼠肝脏葡萄糖代谢和肝纤维化形成的影响。方法:（1）建立去迷走神经肝脏模型,SD大鼠32只分模型组及对照组,每组16只。模型组切除迷走神经肝支,对照组仅行开腹神经探查手术。术后每周各采集1次肝脏组织标本,每次4只,连续4周。标本进行VAChT免疫组化,观察肝脏胆碱能神经纤维的表达情况。（2）肝糖原及肝纤维化指标测定.SD大鼠32只分为实验空腹、实验进食及对照空腹和对照进食4组,各8只。实验组行迷走神经肝支切除,对照组行开腹神经探查手术。各组分别测定肝糖原,以及肝组织HA、LN、PC Ⅲ和CIV含量。结果:模型组去迷走神经3周后肝胆碱能神经明显减少,第4周基本消失。实验组空腹肝糖原含量显著低于对照组（P<0.01）,且进食后亦无明显变化（P<0.05）,而对照组进食后肝糖原增加显著（P<0.01）。实验组HA、LN、PC Ⅲ和CIV含量明显高于对照组（P<0.01或P<0.05）。结论:大鼠去除迷走神经后4周,能够达到完全去神经肝脏状态,肝脏去迷走神经后葡萄糖的合成和储存能力显著降低,去神经后肝脏的抗纤维化能力明显减弱。