橙皮苷对胰岛素抵抗HepG2细胞体外糖代谢的影响

目的探讨橙皮苷(hesperidin)对胰岛素抵抗HepG2细胞体外糖代谢的影响。方法采用高浓度胰岛素(INS)持续作用HepG2 12h建立胰岛素抵抗(IR-HepG2)模型,同时培养液中给予不同质量浓度橙皮苷(10,40和60μg.mL-1)或盐酸二甲双胍(30μg.mL-1)干预。药物作用12h后,换含低浓度INS的培养液培养细胞12h,使细胞同步化。然后,测定各组细胞葡萄糖消耗量、细胞内肝糖原含量、己糖激酶(hexokinase,HK)和丙酮酸激酶(pyruvate kinase,PK)的活力。结果与正常组相比,模型组细胞葡萄糖消耗量、肝糖原含量及HK和PK酶活力显著下降(P<0.01);与模型组相比,40和60μg.mL-1的橙皮苷可极显著增加IR-HepG2细胞葡萄糖消耗量、肝糖原合成量及HK酶活力(P<0.01),显著增加PK酶活力(P<0.05)。结论橙皮苷可增加IR-HepG2细胞对葡萄糖的利用,增加肝糖原合成量,提高HK、PK活力,从而促进IR-HepG2细胞糖代谢,改善胰岛素抵抗能力。     

特拉唑嗪对原发性高血压病人的血压、血脂及糖代谢的影响

目的：观察特拉唑嗪对３８例（男性２２例，女性１６例；年龄５６±ｓ８ａ）原发性高血压Ｉ期病人血压、血脂及糖代谢的影响。方法：特拉唑嗪首剂于晚上睡前服１ｍｇ，以后根据血压情况逐渐增量，最大剂量为１０ｍｇ／ｄ，８ｗｋ为一个疗程。结果：特拉唑嗪治疗后，血压下降（Ｐ＜０．０１），糖负荷曲线略降低，胰岛素水平（Ｉｎｓ）及胰岛素抵抗（ＩＳＲ）降低（Ｐ＜０．０１），心率及血脂无改变（Ｐ＞０．０５）。结论：特拉唑嗪对原发性高血压Ｉ期者，在改善血压的同时，不影响脂代谢，对糖代谢、胰岛素及ＩＳＲ有益。     

Alpha-lipoic acid attenuates insulin resistance and improves glucose metabolism in high fat diet-fed mice

Aim:

To investigate whether alpha-lipoic acid (ALA) could attenuate the insulin resistance and metabolic disorders in high fat diet-fed mice.

Methods:

Male mice were fed a high fat diet (HFD) plus ALA (100 and 200 mg·kg⁻¹·d⁻¹) or HFD plus a positive control drug metformin (300 mg·kg⁻¹·d⁻¹) for 24 weeks. During the treatments, the relevant physiological and metabolic parameters of the mice were measured. After the mice were euthanized, blood samples and livers were collected. The expression of proteins and genes related to glucose metabolism in livers were analyzed by immunoblotting and real time-PCR.

Results:

HFD induced non-alcoholic fatty liver disease (NAFLD) and abnormal physiological and metabolic parameters in the mice, which were dose-dependently attenuated by ALA. ALA also significantly reduced HFD-induced hyperglycemia and insulin resistance in HFD-fed mice. Furthermore, ALA significantly upregulated the glycolytic enzymes GCK, HK-1 and PK, and the glycogen synthesis enzyme GS, and downregulated the gluconeogenic enzymes PEPCK and G6Pase, thus decreased glucose production, and promoted glycogen synthesis and glucose utilization in livers. Moreover, ALA markedly increased PKB/Akt and GSK3β phosphorylation, and nuclear carbohydrate response element binding protein (ChREBP) expression in livers. Metformin produced similar effects as ALA in HFD-fed mice.

Conclusion:

ALA is able to sustain glucose homeostasis and prevent the development of NAFLD in HFD-fed mice.     

成纤维细胞生长因子-21改善胰岛素抵抗肝细胞对葡萄糖的吸收及机制

目的建立正常人肝细胞(HL-7702)胰岛素抵抗(in-sulin resistance,IR)模型,探讨成纤维细胞生长因子-21(FGF-21)对胰岛素抵抗的改善作用及其机制。方法培养HL-7702细胞,利用高浓度胰岛素和地塞米松(dexametha-sone,DEX)诱导IR模型。GOD-POD试剂盒测定细胞葡萄糖消耗量,Western blot检测GLUT1和磷酸化ERK1/2表达水平。结果 FGF-21促进HL-7702细胞葡萄糖的消耗且呈剂量依赖性,与胰岛素联合用药提高葡萄糖消耗量。在随后IR模型实验中,FGF-21改善IR模型细胞葡萄糖消耗量。FGF-21作用24 h,GLUT1的表达量明显增高,p-ERK1/2的含量增强。当加入ERK1/2特异性抑制剂PD98059,FGF-21促ERK1/2的磷酸化作用被抑制。IR模型中,FGF-21仍能提高p-ERK1/2的含量。结论 FGF-21促进HL-7702细胞对葡萄糖的消耗,改善IR HL-7702细胞葡萄糖消耗量,提高葡萄糖转运蛋白GLUT1和ERK1/2磷酸化的表达。     

The fatty acid-rich fraction of Eruca sativa (rocket salad) leaf extract exerts antidiabetic effects in cultured skeletal muscle,adipocytes and liver cells

Context: Eruca sativa Mill. (Brassicaceae), commonly known as rocket salad, is a popular leafy-green vegetable with many health benefits.

Objective: To evaluate the antidiabetic activities of this plant in major insulin-responsive tissues.

Materials and methods: Five E. sativa leaf extracts of varying polarity were prepared (aqueous extract, 70% and 95% ethanol extracts, the n-hexane-soluble fraction of the 95% ethanol extract (ES3) and the defatted 95% ethanol extract). Eruca sativa extracts were investigated through a variety of cell-based in vitro bioassays for antidiabetic activities in C2C12 skeletal muscle cells, H4IIE hepatocytes and 3T3-L1 adipocytes. Guided by the results of these bioassays, ES3 was fractionated into the saponifiable (SM) and the unspaonifiable (USM) fractions. Glucose uptake was measured using [³H]-deoxy-glucose, while the effects on hepatic glucose-6-phosphatase (G6Pase) and adipogenesis were assessed using Wako AutoKit Glucose and AdipoRed assays, respectively.

Results: ES3 and its SM fraction significantly stimulated glucose uptake with EC₅₀ values of 8.0 and 5.8?μg/mL, respectively. Both extracts significantly inhibited G6Pase activity (IC₅₀ values of 4.8 and 9.3?μg/mL, respectively). Moreover, ES3 and SM showed significant adipogenic activities with EC₅₀ of 4.3 and 6.1?μg/mL, respectively. Fatty acid content of SM was identified by GC-MS. trans-Vaccenic and palmitoleic acids were the major unsaturated fatty acids, while palmitic and azelaic acids were the main saturated fatty acids.

Discussion and conclusion: These findings indicate that ES3 and its fatty acid-rich fraction exhibit antidiabetic activities in insulin-responsive cell lines and may hence prove useful for the treatment of type 2 diabetes.     

Effect of nicardipine on insulin secretion,glucose and lipid metabolism in hypertensive,non-insulin dependent diabetics

Summary Certain acute and chronic metabolic effects of nicardipine have been studied in 20 patients with non-insulin dependent diabetes (NIDD). An intravenous glucose tolerance test (i.v. GTT, glucose 0.33 g/kg as a bolus) and the corresponding insulin response were assessed at the end of a 4 week placebo period, after the first dose and on administration for 12 weeks of nicardipine 20 mg t.i.d.The glucose and insulin responses to the i.v. GTT, evaluated as incremental AUCs, did not change significantly (glucose 30.5 mg/dl·90 min on placebo, 33.1 mg/dl·90 min acutely and 31.4 mg/dl·90 min on chronic administration of nicardipine; insulin 2.08 µU/ml·90 min on placebo, 1.87 µU/ml·90 min acutely and 1.93 µU/ml·90 min after chronic nicardipine). Glucose removal rate (KG) following the i.v. GTT was 0.73%/min on placebo 0.75%/min on acute administration and 0.8%. min^–1 with chronic nicardipine.Active treatment produced a significant reduction of blood pressure (from 187/96 mm Hg on placebo to 166/89 mm Hg acutely and 152/83 mm Hg after 12 weeks of nicardipine treatment). It is concluded that the calcium antagonist nicardipine was an effective antihypertensive drug, and that it did not cause deterioration of metabolic control in hypertensive patients with NIDD.     

替米沙坦对部分中老年高血压病胰岛素抵抗及糖、脂代谢的影响

目的 观察替米沙坦对部分中老年高血压病胰岛素抵抗及糖、脂代谢的影响.方法 选择中老年高血压病80例(年龄≥60岁),口服替米沙坦治疗8周.治疗前、后观察患者的体重指数(BMI)、收缩压(SBP)、舒张压(DBP)、空腹血糖(FPG)、餐后2小时血糖(2hPG)、三酰甘油(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR).结果 替米沙坦治疗后,患者的BMI、SBP、DBP、FPG、2hPG、TG、TC、LDL-C、FINS、HOMA-IR均显著下降(P＜0.05),HDL-C显著提高(P＜0.05).结论 替米沙坦除了有较好的降压效果,还可以改善中老年高血压病患者胰岛素抵抗及糖、脂代谢异常,从而预防心脑血管疾病的发生.     

阿立哌唑治疗男性精神分裂症的疗效及对糖脂代谢的影响

目的 探讨阿立哌唑与利培酮对精神分裂症患者的疗效及对患者糖脂代谢的影响.方法 将80例精神分裂症患者采用随机数字表法分为阿立哌唑组(40例)为观察组和利培酮组(40例)为对照组,疗程8周.两组于治疗前、治疗后2、4、6、8周末采用阳性与阴性症状量表(PANSS)进行评分,并检测血总胆固醇(TC),三酰甘油(TG),高密度脂蛋白(HDL),低密度脂蛋白(LDL),空腹血糖.结果 观察组显效率77.5%,有效率90.0%,对照组显效率80.0%,有效率92.5%,两组疗效比较差异无统计学意义(P>0.05);治疗前后TC,TG,HDL,LDL和空腹血糖:观察组差异无统计学意义(P>0.05),对照组均差异有统计学意义(P<0.05).结论 阿立哌唑治疗精神分裂症的疗效与利培酮相当,对精神分裂症患者的糖脂代谢几乎没有影响,而利培酮对患者的糖脂代谢影响更明显.     

荔枝核皂苷对地塞米松致胰岛素抵抗糖尿病大鼠血糖血脂的影响

目的　研究荔枝核皂苷对地塞米松 (DX)致胰岛素抵抗 (insulinresistance,IR)大鼠血糖、血脂的影响。方法　采用DX诱导IR大鼠模型 ,观察荔枝核皂苷和罗格列酮对病鼠空腹血糖 (FBG)和口服葡萄糖耐量试验 (OGTT)后 2h血糖 (2hBG)以及给药后 2h空腹血清血糖 (FSG)、总胆固醇 (TC)、三酰甘油 (TG)、高密度脂蛋白 -胆固醇 (HDL -C)、低密度脂蛋白 -胆固醇(LDL -C)、丙二醛 (MDA) ,以及丙氨酸氨基转移酶 (ALT)、天冬氨酸氨基转移酶 (AST)、超氧化物歧化酶 (SOD)活性等指标的影响。结果　荔枝核皂苷改善DX致IR模型大鼠的IGT ,降低OGTT后 2h期BG和FSG(P <0 .0 5 ) ;并能显著降低病鼠TC、TG、LDL -C含量 (P <0 .0 5 - 0 .0 1) ,显著提高HDL -C含量 (P <0 .0 5 ) ;抑制AST、ALT活性 (P <0 .0 5 ) ,降低AST/ALT ;加强SOD活性和降低MDA的含量 (P <0 .0 1) ,增强抗氧化能力。结论　荔枝核皂苷对DX致IR大鼠有降血糖、调血脂改善肝功能等的作用 ,显示抗氧化作用     

Comparison of acute and subacute effects of deflazacort and prednisone on glucose metabolism in man

Summary Corticosteroid treatment produces glucose intolerance with insulin resistance. Recent reports have indicated that deflazacort (DF) is significantly less diabetogenic than prednisone (PN). A euglycaemic hyperinsulinaemic (100 µU/ml) glucose clamp (EHGC) and ³H-glucose infusion for 240 min were performed in 6 healthy volunteers (HV) after administration of 15 mg PN or 18 mg DF, 12 h and 2 h before test. The glucose metabolic clearance rate (MCR) was significantly (p=0.02) higher after DF (4.75±0.58 ml/min·kg) than after PN (3.31±0.27 ml/min·kg). Basal hepatic glucose production (HGP) was significantly (p=0.003) lower after DF (3.58±0.33 mg/kg·min) than after PN (4.44±0.23 mg/kg·min). A similar pattern was obtained for glucose volume (GV) and glucose pool (GP). The kinetic parameters of insulin were not significantly different after the two drugs. After 7 day of PN 30 mg/day or DF 36 mg/day, EHGC and ³H-glucose infusion for 240 min were performed in 10 HV. Glucose MCR values were significantly (p=0.03) higher after DF (5.03±0.91 ml/min·kg) than after PN (2.80±0.26 ml/min·kg). HGP values did not different significantly after the two drugs. GV (p=0.001) and GP (p=0.002) were significantly lower after DF than after PN. Insulin kinetics were not significantly different after the two drugs. It is concluded that on acute and 7-day administration to healthy subjects DF, in an anti-inflammatory dose equivalent to PN, shows significantly less influence on glucose metabolism.     

Inhibitory effects of crocetin on high glucose-induced apoptosis in cultured human umbilical vein endothelial cells and its mechanism

Dysfunction of endothelial cell is considered as a major cause of vascular complications in diabetes. Crocetin has been shown to have strong antioxidant activities. In present study, we tested whether crocetin inhibited high glucose-induced apoptosis in cultured human umbilical vein endothelial cells (HUVEC_s) and to explore its possible mechanism. Exposure to high glucose (33 mM) for 72h induced a pronounced increase in apoptosis compared with normal glucose (5.5 mM), as evaluated by cell chromatin staining with Hoechst 33,258 and cell death detection ELISA. High glucose attenuated activation of Akt and endothelial nitric oxide synthase (eNOS). Crocetin (0.1 μM, 1.0 μM) prevented high glucose-induced apoptosis, which correlates with the increase of activation of p-Akt, following the up-regulation of eNOS and NO production. Pretreatment with phosphatidylinositol 3′ kinase (Pl3K) inhibitor LY294002 or eNOS inhibitor N^G-nitro-arginine methyl ester (LN or L-NAME) inhibited crocetin’ effect on p-Akt or eNOS, respectively. For the first time, results of our study suggest that crocetin inhibits high glucose-induced apoptosis, at least partly, via Pl3K/Akt/eNOS pathway in HUVEC_s and crocetin may exert a beneficial effect in preventing diabetes-associated cardiovascular complications.     

三种抗精神病药治疗女性首发精神分裂症对糖脂代谢及催乳素的影响

目的评价奥氮平、利培酮及阿立哌唑对女性首发精神分裂症患者糖脂代谢及催乳素水平的影响。方法随机选择女性首发精神分裂症患者97例,分别使用奥氮平、利培酮及阿立哌唑治疗8周。治疗前及治疗期间每周记录体重变化,治疗前及治疗第2、4、8周末检验空腹血糖、甘油三脂、总胆固醇及高密度脂蛋白胆固醇、催乳素水平。结果在研究结束时,三组患者体重改变,血脂及催乳素水平变化均有显著性差异,空腹血糖变化无显著性差异。结论对于首发女性分裂症患者,奥氮平及利培酮对体重增加,脂代谢及催乳素水平有明显影响,而阿立哌唑则影响轻微。短期使用三种药物不影响患者空腹血糖水平。     

Effects of butanol fraction of Ziziphus mucronata root ethanol extract on glucose homeostasis,serum insulin and other diabetes-related parameters in a murine model for type 2 diabetes

Context: Ziziphus mucronata Willd (Rhamnaceae) is currently used in Nigerian traditional treatment of diabetes mellitus. However, detailed information on the antidiabetic potential of the plant parts is presently unknown.

Objectives: The present study investigated the antidiabetic effects of the butanol fraction of Z. mucronata root (ZMBF) in a type 2 diabetes (T2D) model of rats.

Materials and methods: T2D was induced in rats by feeding a 10% fructose solution ad libitum for two weeks followed by an intraperitoneal injection of streptozotocin (40?mg/kg bw) and the animals were orally treated with ZMBF 150 or 300?mg/kg bw for five days a week for four weeks. Food and fluid intake, body weight changes and blood glucose levels were monitored during the experiment while other blood and organ specific diabetes-associated parameters were measured at the end of the experiment.

Results: After four-week treatment, significantly (p?p?>?0.05) affected by the treatment of ZMBF.

Conclusion: Results of this study suggest that ZMBF treatment, at 300?mg/kg bw, possess antidiabetic activity, but could not ameliorate some diabetes-related parameters in type 2 diabetic rats.     

Molecular mechanisms underlying the effects of cyclosporin A and sirolimus on glucose and lipid metabolism in liver,skeletal muscle and adipose tissue in an in vivo rat model

Cyclosporin A (CsA) and sirolimus (SRL) are immunosuppressive agents (IAs) associated with dyslipidemia, insulin resistance and new onset diabetes after transplantation (NODAT). However, the molecular mechanisms involved are not fully understood. We investigated the effects of six-week treatment of either CsA or SRL on glucose and lipid metabolism in Wistar rats. The results show that, compared with vehicle-treated rats, SRL-treated rats were significantly lighter starting at week 5. CsA or SRL caused glucose intolerance, increased storage of lipids in the liver and skeletal muscle, and decreased the insulin-stimulated glucose uptake in isolated adipocytes. Furthermore, these agents significantly decreased genes involved in insulin action and glucose uptake, such as, IRS-1, Glut4 and Glut1, and increased genes and/or proteins involved in hepatic lipogenesis and gluconeogenesis, while decreasing them in adipose tissue. After either treatment PGC1α gene expression was down regulated in skeletal muscle, an important player in fatty acid oxidation. Moreover, there was an increase in IL-6 gene expression in adipose tissue in the SRL-treated rats, suggesting stimulation of lipolysis. The results of the present study suggest that CsA and SRL lead to metabolic alterations in liver, muscle and adipose tissue, which may contribute to the development of dyslipidemia and insulin resistance associated with immunosuppressive therapy.     

胰高血糖素样肽-1对胰岛素抵抗3T3-L1脂肪细胞脂肪酸代谢的作用及机制

目的研究胰高血糖素样肽-1(GLP 1)对胰岛素抵抗3T3 L1脂肪细胞脂肪酸代谢的作用及机制。方法采用高糖高胰岛素造成胰岛素抵抗3T3 L1脂肪细胞模型,通过ELISA及Western blot等方法观察GLP 1对此模型脂肪酸代谢的影响及机制。结果 ELISA结果显示,GLP 1对胰岛素抵抗3T3 L1脂肪细胞中游离脂肪酸(FFA)的含量影响与胰岛素相关:在有胰岛素(100 nmol.L-1)存在时,GLP 1可增加上清液中FFA含量;而无胰岛素存在时,GLP 1可减少上清液中FFA含量。GLP 1升高细胞中脂肪酸合成酶(FAS)表达量的作用也必须依赖胰岛素的存在。Western blot结果显示在有胰岛素存在时,GLP 1可促进蛋白激酶B(PKB)磷酸化;而无胰岛素存在时则无此作用。PKB磷酸化的抑制剂LY294002或Wortmannin可阻断胰岛素存在时GLP 1对PKB磷酸化的促进作用及对上清液FFA含量的升高作用。另外,在有(无)胰岛素存在时,GLP 1均可降低激素敏感性脂肪酶(HSL)的蛋白表达量。结论 GLP 1可增强胰岛素抵抗3T3 L1脂肪细胞对胰岛素的敏感性并降低HSL的含量;胰岛素可影响GLP 1对胰岛素抵抗3T3 L1脂肪细胞脂肪酸代谢的调节作用。     

Effects of inhibitors of arachidonic acid metabolism on calcium uptake and catecholamine release in cultured adrenal chromaffin cells

The possibility that arachidonic acid metabolism is involved in the secretory process in cultured adrenal chromaffin cells was investigated by studying the effects of lipoxygenase inhibitors and cyclooxygenase inhibitors on 45Ca2+ uptake and catecholamine release. Lipoxygenase inhibitors, which have different chemical structures, such as nordihydroguaiaretic acid (NDGA), 3-amino-1-(3-trifluoromethylphenyl)-2-pyrazoline (BW755C) and 2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone (AA861) all prevented the catecholamine release evoked by carbamylcholine and high K+. In contrast, cyclooxygenase inhibitors, such as aspirin and indomethacin failed to inhibit the carbamylcholine-evoked catecholamine release. Lipoxygenase inhibitors also inhibited 45Ca2+ uptake into the cells stimulated by carbamylcholine and high K+. Lipoxygenase inhibitors inhibited 45Ca2+ uptake and catecholamine release with similar potency. Slightly higher concentrations of lipoxygenase inhibitors were required to inhibit high K+-evoked effects compared to those evoked by carbamylcholine. The inhibitory effects of these inhibitors on carbamylcholine-evoked catecholamine release was different in its nature from the inhibitory effect of verapamil, a blocker of the Ca2+ channel, and was not due to a competitive antagonism at cholinergic receptor site. Moreover, these lipoxygenase inhibitors did not inhibit the binding of [3H]nitrendipine to chromaffin cell homogenate. The data suggest that lipoxygenase inhibitors prevent the catecholamine release from cultured adrenal chromaffin cells by blocking Ca2+ uptake. It might be possible that lipoxygenase product(s) is involved in the Ca2+ translocation system in these cells.     

Exposure to 2,4-dichlorophenoxyacetic acid alters glucose metabolism in immature rat Sertoli cells

The purpose of this study was to determine the effects of 2,4-D, an herbicide used worldwide also known as endocrine disruptor, in Sertoli cell (SC) metabolism.Immature rat SCs were maintained 50 h under basal conditions or exposed to 2,4-D (100 nM, 10 μM and 1 mM). SCs exposed to 10 μM and 1 mM of 2,4-D presented lower intracellular glucose and lactate content. Exposure to 10 μM of 2,4-D induced a significant decrease in glucose transporter-3 mRNA levels and phosphofructokinase-1 mRNA levels decreased in cells exposed to 100 nM and 10 μM of 2,4-D. Exposure to 100 nM and 10 μM also induced a decrease in lactate dehydrogenase (LDH) mRNA levels while the LDH protein levels were only decreased in cells exposed to 1 mM of 2,4-D.Exposure to 2,4-D altered glucose uptake and metabolization in SCs, as well as lactate metabolism and export that may result in impaired spermatogenesis.     

溪黄草水提物对高糖诱导的大鼠HBZY-1细胞炎症反应和氧化应激的抑制作用以及对TLR 4/NF-κB/NLRP 3通路的作用

目的：溪黄草水提物（RWE）对高糖诱导的大鼠HBZY-1细胞炎症反应和氧化应激的抑制作用以及对TLR 4/NF-κB/NLRP 3通路的作用。方法：用高糖（HG,30 mmol·L^-1）孵育大鼠肾小球细胞株HBZY-1细胞,MTT法测定不同浓度RWE（5,10,20 mg·mL^-1）对HG环境下HBZY-1细胞增殖的影响,测定RWE对HG诱导的HBZY-1细胞氧化应激水平和炎性细胞因子表达的影响,同时测定其对细胞TLR4/NF-κB/NLRP3信号通路的影响。结果：HG能诱导HBZY-1细胞增殖,提高MDA、IL-6、IL-1β、TNF-α水平和TLR 4/NF-κB/NLRP 3信号通路的表达,降低SOD和GSH水平;RWE减弱细胞的增殖能力,降低MDA、IL-6、IL-1β和TNF-α的水平,提高SOD和GSH水平,抑制TLR 4/NF-κB/NLRP 3信号通路的表达。结论：RWE对HG诱导的HBZY-1细胞具有保护作用,其作用机制主要是抑制炎症反应和氧化应激,TLR 4/NF-κB/NLRP 3信号通路可能参与RWE对细胞的保护作用。     

The effects of di 2-ethyl hexyl phthalate (DEHP) on cellular lipid accumulation in HepG2 cells and its potential mechanisms in the molecular level

Diethylhexyl phthalate (DEHP) is suspected to be an inevitable factor related to metabolic disease. Our previous study demonstrated that excess DEHP could exacerbate non-alcoholic fatty liver disease (NAFLD) in SD rats. Addressing the terra incognita in DEHP-induced metabolic dysfunction, this study used HepG2 cells to investigate the potential mechanisms involved in DEHP-induced toxicity in vitro. The cells were established lipid overload model with oleic acid and BSA, then exposed to different concentrations (5, 10, 25, 50, 100?μmol/l DEHP) of DEHP for further analysis. The Oil Red O staining results showed that DEHP could promote lipid accumulation in cells. The level of superoxide dismutase (SOD) and malondialdehyde (MDA) changed suggested the balance of oxidative stress was disrupted. Additionally, western blot analysis showed that DEHP could promote the expression of peroxisome proliferator-activated receptor α (PPARα) and sterol regulatory element-binding protein 1c (SREBP-1c). By quantifying the expressions of the two proteins, it is of interest to determine that DEHP could promote lipid accumulation in hepatocytes via activating the SREBP-1c and PPARα-signaling pathway.     

Isoliquiritigenin impairs insulin signaling and adipocyte differentiation through the inhibition of protein-tyrosine phosphatase 1B oxidation in 3T3-L1 preadipocytes

Isoliquritigenin (ISL) is an abundant dietary flavonoid with a chalcone structure, which is an important constituent in Glycyrrhizae Radix (GR). ISL exhibits anti-oxidant activity, and this activity has been shown to play a beneficial role in various health conditions. However, it is unclear whether the anti-oxidant activity of ISL affects insulin signaling pathway and lipid accumulation of adipocytes. We sought to investigate the effects and molecular mechanisms of ISL on insulin-stimulated adipogenesis in 3T3-L1 cells. We investigated whether ISL attenuates insulin-induced Reactive Oxygen Species (ROS) generation, and whether ISL inhibits the lipid accumulation and the expression of adipogenic-genes during the differentiation of 3T3-L1 cells. ISL blocked the ROS generation, suppressed the lipid accumulation and the expression of adipocyte-specific proteins, which are increased in response to insulin stimulation during adipocyte differentiation of 3T3-L1 cells. We also investigated whether the anti-oxidant capacity of ISL is involved in regulating the molecular events of insulin-signaling cascade in 3T3-L1 adipocytes. ISL restores PTP1B activity by inhibiting PTP1B oxidation and IR/PI3K/AKT phosphorylation during the early stages of insulin-induced adipogenesis. Our findings show that the anti-oxidant capacity of ISL attenuated insulin IR/PI3K/AKT signaling through inhibition of PTP1B oxidation, and ultimately attenuated insulin-induced adipocyte differentiation of 3T3-L1 cells.