不同膳食油脂对高脂血症大鼠脂质代谢影响的比较研究

目的比较4种脂肪酸组成迥异的膳食油脂对高脂血症大鼠脂质代谢的影响,并初步探讨其作用机制。方法将OLETF大鼠28只分为4组,喂以AIN76基本配方饲料,基础油脂含量为8%,各组分别添加2%棕榈油、琉璃苣油、紫苏油和鱼油。4 w后,测定大鼠空腹血清甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、游离脂肪酸(NEFA)、葡萄糖浓度,肝脏TG、TC、磷脂(PL)浓度以及肝脏脂质代谢相关酶脂肪酸合成酶(FAS)、苹果酸酶(ME)、葡萄糖6磷酸脱氢酶(G6PDH)和肉碱棕榈酰转移酶(CPT-1,CPT-2)的mRNA表达。结果与棕榈油组比,琉璃苣油组血清中NEFA、TG含量显著降低(P<0.05),TC、HDL-C含量明显升高(P<0.05)。紫苏油组血清中NEFA、TG含量显著降低(P<0.05)。鱼油组与其它组相比,各项指标含量均显著降低(P<0.05)。琉璃苣油和紫苏油组可明显降低肝脏TG和TC浓度(P<0.05),鱼油组显著降低肝脏TG浓度(P<0.05),对TC浓度无明显影响。此外,琉璃苣油、紫苏油和鱼油组可显著抑制肝脏脂肪合成相关酶的mRNA表达(P<0.05),同时显著增加脂肪酸分解酶mRNA表达(P<0.05)。结论相比于棕榈油组,摄食琉璃苣油、紫苏油和鱼油可通过抑制肝脏脂肪酸合成和促进脂肪酸分解,降低高脂血症大鼠血清和肝脏脂肪水平。     

Dietary diacylglycerol-rich oil stimulation of glucose intolerance in genetically obese rats

The effects of dietary 1,3-diacylglycerol-rich oil (DG oil) on glucose and lipid metabolism were investigated in comparison with triacylglycerol (TG) oil in female genetically obese Wistar fatty rats. The obese rats and their lean littermates (8 wk old) were fed a synthetic diet containing 10%, (w/w) DG or TG oil for 5 wk. The body weights, abdominal fat weights, and the plasma and liver TG concentrations were not significantly different due to dietary fat type in the obese and lean rats. The plasma glucose concentrations were significantly elevated by dietary DG oil as compared to TG oil in the portal vein and inferior vena cava of obese and lean rats. The plasma free fatty acid concentrations were markedly elevated by dietary DG oil as compared to TG oil in the portal vein and inferior vena cava of both genotype rats, particularly in the obese rats. In the glucose tolerance test, the obese rats fed DG oil showed glucose intolerance, possibly due to the markedly elevated plasma free fatty acids. Thus, the effects of dietary DG oil on lipid-lowering effects and anti-obesity were not observed in either genotype in the present study. Moreover, it is remarkable that glucose intolerance was induced by dietary DG oil in the genetically obese rats. dietary     

高脂饲料对OLETF大鼠糖代谢及血清磷脂脂肪酸组成的影响

目的:观察高脂饲料对自发性2型糖尿病模型OLETF大鼠糖代谢及血清磷脂脂肪酸组成的影响。方法:将20只14w雄性OLETF大鼠随机分为两组,分别以高脂及标准饲料喂饲10w,两种饲料中饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸占总脂肪酸的百分含量相似。大鼠第24w龄时进行口服糖耐量试验,同时测定大鼠的胰岛素水平和血清磷脂脂肪酸组成。结果:实验期间两组大鼠总进食量无统计学差异,但高脂饲料组大鼠体重明显高于标准饲料组(P<0.01);口服糖耐量试验和胰岛素水平测定结果表明,两组大鼠的糖代谢状态无统计学差异;血清磷脂脂肪酸组成中,除总n-6PUFA和18:3(n-3)的百分含量无统计学差异外,其他各脂肪酸组分在两组间的差异均具有统计学意义(P<0.01)。结论:在饲料脂肪酸组成保持可比的情况下,饲料脂肪量的增加可使OLETF大鼠的体重明显增加,而对糖代谢的影响不明显,同时对OLETF大鼠血清磷脂脂肪酸组成产生明显影响。     

维生素E和不同脂肪酸对大鼠血糖、血脂及脂质过氧化水平的影响

目的观察维生素E和饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸对大鼠血糖、血脂及脂质过氧化物的影响.方法雄性SD大鼠48只随机分成6组,分别为猪油组、橄榄油组、橄榄油 维生素E组、葵花籽油组和猪油 维生素E组、葵花籽油 维生素E组.各组大鼠的饲料中脂肪占总能量的30.7%,蔗糖占总能量的14.8%,喂饲6周后采血测定大鼠血清葡萄糖耐量、胰岛素、总胆固醇(TG)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、血清丙二醛(MDA)、血清谷胱甘肽过氧化物酶(GSH-Px)和血清维生素E浓度.结果橄榄油组大鼠的血清TG、TC、空腹血糖、空腹胰岛素和餐后2 h血糖均显著低于猪油组;血清MDA低于葵花籽油组,血清GSH-Px、HDL-C高于葵花籽油组和猪油组(P＜0.05);葵花籽油 维生素E组和猪油 维生素E组大鼠的血清TC、TG、餐后2 h血糖、血清MDA均显著低于相应的未加维生素E组,血清维生素E、HDL-C、GSH-Px高于相应的未加维生素E组(P＜0.05).结论维生素E和单不饱和脂肪酸有利于正常的葡萄糖代谢,可能与降低血清TC、TG,减少脂质过氧化物的产生,减轻机体组织的胰岛素抵抗有关.     

Hypolipidemic effect of dietary diacylglycerol oil in Sprague-Dawley rats fed a normal diet

The present study compared the effects of dietary diacylglycerol (DG) and triacylglycerol (TG) oil on lipid metabolism in rats fed a 5% fat (AIN-76) diet for 6 weeks. The plasma and hepatic lipids, hepatic cholesterol-regulating enzyme activity, and hepatic and adipose tissue fatty acid metabolism enzyme activities were determined. Among plasma lipids, triglyceride, free fatty acid, and phospholipid concentrations were significantly lower in the DG group than in the TG group. A lower plasma TG level was accompanied by an increase in adipocyte lipoprotein lipase activity. The hepatic triglyceride level was significantly (P < .001) lowered in the DG group, which was attributable to an increased fatty acid oxidation enzyme (beta-oxidation) activity and a reduced fatty acid synthesis enzyme (glucose-6-phosphate dehydrogenase) activity. The plasma cholesterol concentration was significantly lower in the DG group and was accompanied by a lower hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity. The DG oil used in this study was beneficial for enhancing lipid metabolism with apparent hypolipidemic effects.     

不同膳食脂肪对糖耐量及胰岛素敏感性的影响

目的:比较4种膳食脂肪对大鼠糖耐量及胰岛素敏感性的影响。方法:将50只SD大鼠随机分为5组,分别为紫苏油组、葵花籽油组、橄榄油组、猪油组和基础饲料组。各膳食脂肪组大鼠的脂肪摄入量占总能量的30.4%。喂养6 w后,进行口服葡萄糖耐量试验(OGTT),测定血清胰岛素、甘油三酯、总胆固醇等指标,并计算胰岛素敏感指数(ISI)。同时分离附睾脂肪垫并称重。结果:与基础饲料组相比,猪油组大鼠葡萄糖餐后2 h血糖及胰岛素显著升高,ISI显著降低;葵花籽油组和橄榄油组大鼠的餐后2 h血糖显著低于猪油组,ISI显著高于猪油组;紫苏油组大鼠空腹及餐后2h血糖、胰岛素水平均显著低于猪油组,ISI高于猪油组,其中空腹血糖还低于葵花籽油组、橄榄油组和基础饲料组,ISI高于上述组。紫苏油组血清甘油三酯、总胆固醇水平显著低于猪油组和基础饲料组,大鼠附睾脂肪垫相对重量显著低于猪油组。结论:猪油可促使胰岛素抵抗及高血糖的发生,而紫苏油可提高大鼠胰岛素敏感性、改善糖代谢;葵花籽油和橄榄油对胰岛素敏感性和糖耐量的作用介于紫苏油和猪油之间。紫苏油对糖代谢的有利作用可能与其降低血中甘油三酯水平、减少体内脂肪堆积有关。     

二陈汤对高脂饮食大鼠血脂及胰岛素抵抗的影响

目的：观察化痰方（二陈汤）对高脂饮食大鼠血脂及胰岛素抵抗的影响。方法：30只健康成年雄性大鼠按照随机数字表法分为正常组、高脂组和化痰组各10只,正常组给予正常饲料喂养,高脂组和化痰组给予高脂饲料喂养14周,化痰组第11周起给予二陈汤灌胃4周。在第14周末进行葡萄糖耐量实验（OGTT）和胰岛素耐量实验（ITT）,14周后处死大鼠,检测并比较各组血脂TC、TG的含量及第14周各组大鼠OGTT结果和ITT结果。结果：与正常组比较,高脂组大鼠血清中的TC和TG含量均明显升高（P〈0.01）;与高脂组比较,化痰组大鼠血清中的TG含量明显降低（P〈0.01）,TC有所降低,差异也有统计学意义（P〈0.05）。高脂组的空腹血糖明显高于正常组（P〈0.05）,而化痰组空腹血糖与正常组的比较差异无统计学意义（P〉0.05）;糖负荷后,高脂组的各个时间点的血糖均明显高于正常组（P〈0.05或P〈0.01）,而化痰组除了糖负荷后120 min的血糖明显高于正常组外（P〈0.01）,其余时间点与正常组的比较差异均无统计学意义（P〉0.05）。腹腔注射胰岛素后,化痰组各时间点血糖下降幅度均明显高于高脂组,30 min时高脂组血糖降低18%,而化痰组大鼠降低26%。结论：二陈汤能够降低高脂饮食大鼠血脂的含量,改善胰岛素抵抗,值得在临床上推广使用。     

糖耐量正常的多囊卵巢综合征患者糖脂代谢情况分析

目的：探讨糖耐量正常的多囊卵巢综合征（PCOS）患者糖脂代谢情况。方法：对144例根据鹿特丹标准诊断的PCOS患者进行口服葡萄糖耐量试验（OGTT）和胰岛素释放试验（IRT）,月经正常的女性100例作为对照组。结果：与正常对照组相比,PCOS患者0,30,60,180 min的血糖和血胰岛素水平、稳态模型胰岛素抵抗指数（HOMA-IR）、胰岛β细胞功能指数（HOMA-β）及血糖和血胰岛素曲线下面积显著增高（P＜0.05）,此外血脂参数中三酰甘油（TG）、胆固醇（TC）及低密度脂蛋白胆固醇PCOS组高于对照组,高密度脂蛋白胆固醇低于对照组;根据体质量指数（BMI）对糖耐量正常的PCOS组进行分组分析,发现肥胖组（BMI≥25 kg/m2）糖脂代谢能力仍低于非肥胖组（BMI＜25 kg/m2）：肥胖组0,60,120,180 min血糖和血胰岛素水平、HOMA-IR、HOMA-β及TG均高于非肥胖组（P＜0.05）。结论：对糖耐量正常的PCOS患者建议应常规进行OGTT和IRT观察血糖和血胰岛素分泌情况,从而筛查出糖耐量正常但存在胰岛素抵抗的患者,给予早期干预。对糖耐量正常的肥胖PCOS患者,应更加积极地检测并随访其胰岛素、血脂水平。     

Comparisons of glucose and lipid metabolism in rats fed diacylglycerol and triacylglycerol oils

The effects of dietary 1,3-diacylglycerol-rich oil (DG oil) on biochemical findings related to glucose and lipid metabolisms were investigated in comparison with triacylglycerol oil (TG oil) in normal rats. Young (7 wk-old) and old (8 mo-old) rats were fed a synthetic diet containing 10% (by weight) DC or TG oil for 1, 4, 8, or 12 wk. The body weights, epididymal and perirenal adipose tissue weights, and feed efficiency were not significantly different in the dietary oil groups during any feeding period. The plasma and liver triacylglycerol concentrations were not different in the dietary groups, except that the plasma triacylglycerol concentrations were rather lower only in the portal vein of rats fed DG oil. The plasma glucose and free fatty acid concentrations were significantly higher in rats fed DG oil as compared to TG oil. In the old rats fed DG oil for 8 wk, the fasted plasma glucose and insulin concentrations were elevated and glucose intolerance was observed. The insulin receptor expression was not different due to dietary oil, but was markedly reduced with aging. Thus, the anti-obesity and lipid-lowering effects of dietary DG oil were not found. Moreover, it appeared that the glucose intolerance might be induced by dietary DG oil, particularly in the old rats.     

Effects of exercise, diet, and their combination on metabolic-syndrome-related parameters in OLETF rats

This study was conducted to assess the effects of exercise, diet, and their combination on metabolic syndrome (MS) risk factors including visceral fat mass (VFM), glucose intolerance, and dyslipidemia in OLETF rats. Thirty-two male rats were assigned to exercise (OLETF-Ex), dietary treatment (-DT), combination (-Ex&DT), or sedentary (-Sed) groups. Daily voluntary exercise using a rotary wheel was performed in OLETF-Ex. Each treatment was conducted from 21 to 31 wk of age. An oral glucose tolerance test was performed before and after the treatment period. Absolute levels of VFM, subcutaneous fat mass (SFM), and serum lipids including triglyceride, total cholesterol, and LDL-cholesterol (LDL-C) were measured after the treatment period. All therapeutic treatments resulted in significantly lower levels of body weight, VFM, SFM, and serum lipids than in sedentary control rats. All therapeutic treatments were also found to improve indices of oral glucose tolerance. Of the 3 therapeutic treatments, serum LDL-C levels were significantly lower in OLETF-Ex and OLETF-Ex&DT than in OLETF-Sed. The data demonstrate that all therapeutic approaches tested were effective in improving a number of MS-related parameters in OLETF rats. However, exercise-based therapeutic intervention may provide additional benefits for improving fat metabolism in MS patients.     

A high oxidised frying oil content diet is less adipogenic, but induces glucose intolerance in rodents

Oxidised frying oil (OFO) and fish oil have been shown to be peroxisome proliferator-activated receptor (PPAR)alpha activators and their ingestion results in pleotropic peroxisome proliferator responses in rats. To examine the effect of dietary OFO on adiposity, four groups of weanling Sprague-Dawley rats were fed isoenergetically with, respectively, a low fat basal diet containing 5 g/100 g of fresh soybean oil (LSB) or a high fat diet containing 20 g/100 g of fresh soybean oil (HSB), OFO (HO) or fish oil (HF). The tissue mass, cell size and lipid/DNA ratio in the retroperitoneal fat pad and serum leptin levels were lowest in the HO group (P < 0.05), indicating that dietary OFO has a greater anti-adipogenic action than dietary fish oil. However, a tendency to hyperglycaemia was observed in the HO group (P = 0.0528). To examine the effect of dietary OFO on glucose tolerance, three groups of rats and three groups of mice were fed, respectively, the LSB, HSB or HO diet, and an oral glucose tolerance test was performed. After oral glucose load, the area under the curve for blood glucose (AUCglu) over 2 h was significantly higher, and that for serum insulin (AUCins) over 90 min was significantly lower, in the HO group than in the other two groups (P < 0.05). These results demonstrate that, in rats and mice, a high OFO diet is less adipogenic, but induces glucose intolerance.     

Taurine alters respiratory gas exchange and nutrient metabolism in type 2 diabetic rats

OBJECTIVE: To assess the effect of taurine supplementation on respiratory gas exchange, which might reflect the improved metabolism of glucose and/or lipid in the type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. RESEARCH METHODS AND PROCEDURES: Male OLETF rats (16 weeks of age) were randomly divided into two groups: unsupplemented group and taurine-supplemented (3% in drinking water) group. After 9 weeks of treatment, indirect calorimetry and insulin tolerance tests were conducted. The amounts of visceral fat pads, tissue glycogen, the blood concentrations of glucose, triacylglycerol, taurine, and electrolytes, and the level of hematocrit were compared between groups. A nondiabetic rat strain (Long-Evans Tokushima Otsuka) was used as the age-matched normal control. RESULTS: The indirect calorimetry showed that the treatment of OLETF rats with taurine could reduce a part of postprandial glucose oxidation possibly responsible for the increase of triacylglycerol synthesis in the body. Taurine supplementation also improved hyperglycemia and insulin resistance and increased muscle glycogen content in the OLETF rats. Supplementation with taurine increased the blood concentration of taurine and electrolyte and fluid volume, all of which were considered to be related to the improvement of metabolic disturbance in OLETF rats. DISCUSSION: Taurine supplementation may be an effective treatment for glucose intolerance and fat/lipid accumulation observed in type 2 diabetes associated with obesity. These metabolic changes might be ascribed, in part, to the alteration of circulating blood profiles, where the improved hyperglycemia and/or the blood accumulation of taurine itself would play roles.     

不同来源膳食蛋白质对大鼠体重及其血脂的影响

目的探讨不同膳食蛋白质摄入对大鼠体重及其血脂的长期动态影响。方法选用36只雄性成年Wistar大鼠,按体重随机分为酪蛋白组、大豆蛋白组和谷豆蛋白混合组,喂养12周,检测大鼠在体重及其血脂上的变化。结果大豆蛋白组体重、脂肪湿重、脂体比、TG和TC水平均显著低于酪蛋白组相应指标(P<0.05),HDL-C水平与酪蛋白组相比无统计学差异;谷豆蛋白混合组TC和TG水平均显著低于酪蛋白组和大豆蛋白组(P<0.05),HDL-C水平高于酪蛋白组,有统计学差异(P<0.05)。结论大豆蛋白可以降低大鼠TC和TG水平,谷豆蛋白混合后对TC和TG水平降低作用更明显,并有提高HDL-C的作用。     

Dietary alpha-linolenic acid-rich diacylglycerols reduce body weight gain accompanying the stimulation of intestinal beta-oxidation and related gene expressions in C57BL/KsJ-db/db mice

Dietary fat contributes to the development of obesity. We examined the effect of dietary diacylglycerol (DG), which is a minor component of edible oils, on the development of obesity and expression of genes involved in energy homeostasis in C57BL/KsJ-db/db mice. Mice were fed diets containing either 14 g/100 g (%) triacylglycerol (TG), 10% TG + 4% alpha-linolenic acid-rich TG (ALATG), or 10% TG + 4% alpha-linolenic acid-rich diacylglycerol (ALADG) for 1 mo. Mice fed ALADG, but not ALATG had less body weight gain and higher rectal temperature than the TG-fed controls. These effects were accompanied by up-regulation of acyl-CoA oxidase, medium-chain acyl-CoA dehydrogenase, fatty acid binding protein, and uncoupling protein (UCP)-2 mRNA and beta-oxidation activity in the small intestine. In contrast, the treatments did not affect beta-oxidation and related gene expressions in the liver or UCP-3 mRNA level in skeletal muscle. These results indicate that stimulation of lipid metabolism in the small intestine might be closely related to the antiobesity and thermogenic effects of dietary DG. In addition, structural differences between DG and TG, not variations in the composition of fatty acids, are responsible for the different effects of the lipids.     

Effect of eicosapentaenoic acid ethyl ester v. oleic acid-rich safflower oil on insulin resistance in type 2 diabetic model rats with hypertriacylglycerolaemia

The purpose of the present study was to test whether hyperlipidaemia and insulin resistance in type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats can be improved by dietary supplementation with purified eicosapentaenoic acid (EPA) or oleic acid (OA). Male OLETF rats were fed powdered chow (510 g fat/kg) alone (n 8) or chow supplemented with 10 g EPA- (n 8) or OA- (n 8) rich oil/kg per d from 5 weeks until 30 weeks of age. An oral glucose tolerance test and hyperinsulinaemic euglycaemic clamp was performed at 25 and 30 weeks of age. EPA supplementation resulted in significantly (P<0.05) reduced plasma lipids, hepatic triacylglycerols, and abdominal fat deposits, and more efficient in vivo glucose disposal compared with OA supplementation and no supplementation. OA supplementation was associated with significantly increased insulin response to oral glucose compared with EPA supplementation and no supplementation. Inverse correlation was noted between glucose uptake and plasma triacylglycerol levels (r -086, P<0.001) and abdominal fat volume (r -0.80, P<0.001). The result of oral glucose tolerance test study showed that the rats fed EPA tended to improve glucose intolerance, although this was not statistically significant. Levels of plasma insulin at 60 min after glucose was significantly increased in rats fed OA compared with the other two groups. The results indicate that long-term feeding of EPA might be effective in preventing insulin resistance in diabetes-prone rats, at least in part, due to improving hypertriacylglycerolaemia.     

甘油二酯减肥功能及其可能的代谢机制

目的研究甘油二酯的减肥效果及可能机制。方法(1)5wSD大鼠随机分为3组,每组10只,对照组[饲料甘油三酯(TG)含量7%],高甘油三酯组(TG20%),高甘油二酯(DG)组(DG20%)自由进食喂养8w。实验期间记录动物进食量、排泄量、体重变化,分析脂肪消化率。实验结束后检测动物腹部脂肪重量、血清生化指标变化。(2)餐后血浆脂质动态分析实验采用13w雄性Wistar大鼠(n=50),分两组分别灌胃10%DG或10%TG乳化物,灌胃量0.73ml/100gbw。不同时间麻醉,颈静脉、门静脉分别取血,测血浆中游离脂肪酸(FFA)和TG含量(每次5只)。(3)酮体实验采用6w雄性Wistar大鼠,随机均分三组,分别用20%DG和20%TG乳化物灌胃,对照组用等能量葡萄糖水溶液(GS)作安慰剂。代谢笼中饲养6d,灌胃量0.5ml/100gbw,连续收集144h的尿液,测尿中总酮体量。结果DG组腹部脂肪重量、体重增加及血清TG水平均明显低于高TG组。DG组大鼠门静脉FFA水平明显高于TG组,而颈静脉TG水平略低于TG组,而尿酮体量显著高于TG组。结论膳食DG能明显抑制实验大鼠体重增加,降低血清中性TG水平,与TG组相比,其减肥降血脂效果可能源于其代谢途径不同。     

乳清酸诱导的大鼠非酒精性脂肪肝与糖耐量异常和高血压关系的研究

目的研究长期摄食乳清酸诱导的大鼠脂肪肝、糖耐量及血压的变化及三者之间的关系。方法将Wistar大鼠按体重随机分为对照组和乳清酸两组,前者喂标准饲料,后者喂1%乳清酸饲料。14、30、60、90d后测体重、肝、肾周及附睾脂肪重量,肝甘油三酯(TG)、胆固醇(TC)水平和葡萄糖耐量,并在14、30、45、60、89d测血压变化。结果乳清酸组14、30、60、90 d后测,大鼠体重、体脂肪重量无明显变化,但肝重分别显著增加了46.1%(P<0.001)、35.1%(P<0.001)、40.9%(P<0.001)和42.0%(P<0.05),肝脏TG水平分别升高了383.8%(P<0.05)、301.0%(P<0.05)、538.0%(P<0.01)和1251.5%(P<0.001),肝脏TC水平也有所上升。糖耐量结果为,乳清酸组持续性异常,呈现胰岛素抵抗现象,并伴随发生高血压。结论 1%乳清酸可在短期内建立大鼠非肥胖性非酒精性脂肪肝模型,长期持续,同时伴有糖耐异常现象和高血压。该模型可用于非酒精性脂肪肝与代谢性综合征之间关系的研究。     

Effect of short-term consumption of a high fat diet on glucose tolerance and insulin sensitivity in the rat

The mechanism by which the consumption of high fat, low carbohydrate diets impair glucose tolerance and decrease insulin sensitivity is poorly understood. In an attempt to clarify this question, intravenous glucose tolerance and insulin action in the liver and skeletal muscle were examined in rats after two weeks feeding of either a high fat (HF: 66% energy as fat) or a low fat (LF: 12% energy as fat) diet. Both diets had a P/S ratio (ratio of polyunsaturated to saturated fat in the diet) of 1.3. The high fat diet resulted in mild impairment of intravenous glucose tolerance. Postprandial glucose levels were elevated in the presence of a sustained insulin response. In vitro insulin-stimulated glucose utilisation was decreased significantly in soleus muscle of HF rats, as indicated by decreased [14C]glucose incorporation into muscle glycogen. In contrast, muscle lipogenesis from glucose was not affected by dietary composition. There was no difference in insulin binding to soleus muscle of HF and LF rats, indicating a dissociation between insulin receptor binding and post-receptor metabolic events. Dietary composition did not influence the incorporation of increasing [14C]glucose loads into muscle glycogen or lipid in vivo. However, the HF diet was associated with reduced incorporation of [14C]glucose into lipids and glycogen in the liver and, to a smaller extent, reduced incorporation into adipose tissue lipids in vivo. These results suggest that the mechanism by which HF diets impaired glucose tolerance was mainly hepatic in origin. Decreased glucose uptake, secondary to reduced glucokinase activity, may result in a reduction in glucose utilisation in the liver.     

Association of serum phosphate levels with glucose tolerance, insulin sensitivity and insulin secretion in non-diabetic subjects

BACKGROUND: Hypophosphatemia is associated with impaired glucose tolerance and insulin resistance in primary hyperparathyroidism. However, little is known about the association between serum phosphate and glucose metabolism in healthy subjects. METHODS: We measured fasting serum phosphate levels (SP, normal range 2.6-4.5 mg/dl) and serum calcium (S-Ca, normal range 2.1-2.6 mmol/l) in 881 non-diabetic subjects (341 male/540 female, age: 38+/-1 years, body mass index 25.9+/-0.2 kg/m(2) (mean+/-standard error of the mean). An oral glucose tolerance test (OGTT) with determination of glucose and insulin every 30 min was performed in all subjects. Insulin secretion and insulin sensitivity (IS) were estimated from the OGTT using validated indices. Furthermore, we tested whether serum phosphate predicts glucose tolerance in 115 subjects during a lifestyle intervention program (LIP). RESULTS: Serum phosphate was negatively correlated with 2-h blood glucose levels independent of age, gender and percent body fat (r=-0.13, P<0.0001). This association remained significant after additional adjustment for S-Ca, creatinine and parathyroid hormone. Serum phosphate was positively correlated with IS (r=0.10, P=0.0006), but not with insulin secretion. This was independent of age, gender, percent body fat, S-Ca and serum creatinine. In the subjects taking part in the LIP low serum phosphate levels at baseline were associated with higher postprandial glucose levels. CONCLUSIONS: In non-diabetic subjects, low serum phosphate levels are associated with high 2-h blood glucose levels and reduced IS. Whether low serum phosphate levels are a cause or a consequence of low IS and impairment of glucose tolerance needs to be tested in further studies.     

Increased muscular triglyceride content and hyperglycemia in Goto-Kakizaki rat are decreased by egg white hydrolysate

We investigated the fat metabolic characteristics in non-obese and diabetic Goto-Kakizaki (GK) rat and the effects of dietary egg white hydrolysate (EWH) on glucose and fat metabolism. Wistar (W) and GK (G) rats were placed into dietary casein (WC and GC) or EWH (WE and GE) group, and fed their respective diet for six weeks. Triglyceride (TG) content and stearoyl-CoA desaturase (SCD) indices in the soleus muscle were higher in the GC group than WC group in parallel with worsening serum glucose metabolic parameters. The glucose metabolic parameters were significantly improved in the GE group. The TG accumulation and SCD indices in the soleus muscle were also significantly lower in the GE group than in the GC group. In conclusion, dietary EWH not only improved glucose metabolism but also reduced both TG accumulation and SCD indices in the soleus muscle of GK rat.