血浆胆固醇,甘油三酯水平与胰岛素抵抗的关联

目前对于胰岛素抵抗综合征（X综合征）与脂类代谢紊乱关系的认识尚存争议：某些文献中将高胆固醇血症、高甘油三酯血症均包括于此综合征之中，但一些文献则将高胆固醇血症排除在外，认为高甘油三酯及低HDL－C两者才是该综合征的特征［1－4］。我们分析新疆地区1994年糖尿病普查中做葡萄糖耐量试验（OGTT）的1028例临床资料，探讨血浆总胆固醇及甘油三酯水平是否均与胰岛素抵抗相关，现报道如下。对象和方法全部1028例均为新疆地区1994年万人糖尿病普查中早餐（馒头100g）后2小时血糖（强生公司快速血糖仪测手指血）≥6．67mmol／L者，各…     

甘油三酯-葡萄糖指数与胰岛素抵抗相关代谢性疾病的关系

胰岛素抵抗在2型糖尿病、冠状动脉粥样硬化、非酒精性脂肪性肝病、代谢综合征等代谢紊乱性疾病的发生发展中均起着重要作用。诸多研究已表明,甘油三酯-葡萄糖(triglyceride glucose,TyG)指数可作为评估胰岛素抵抗的代谢指标,与胰岛素抵抗及其相关代谢性疾病之间存在着不同程度的联系。因此,本综述重点阐述TyG指...     

体重正常和肥胖者高胰岛素血症对甘油三酯和载脂蛋白B的影响

０７６体重正常和肥胖者高胰岛素血症对甘油三酯和载脂蛋白Ｂ的影响［英］／ＬｅｗｉｓＧＦ…∥Ｄｉａ－ｂｅｔｅｓ．－１９９３，４２（６）．－８３３～８４２抗胰岛素现象与脂质代谢和动脉粥样硬化的发生都有关。通常认为，ＮＩＤＤＭ病人和肥胖人的高甘油三酯（Ｔｇ）...     

多不饱和脂肪酸对大鼠肝脏甘油三酯蓄积和胰岛素抵抗的影响

目的研究短期多不饱和脂肪酸增高对大鼠肝脏TG含量和胰岛素抵抗的影响。方法给大鼠输注脂肪乳,行清醒高胰岛素-正血糖钳夹试验,观察脂肪乳对葡萄糖利用和肝葡萄糖产生的影响。结果脂肪乳使血浆FFA和TG升高,使肝脏TG和肝葡萄糖产生亦明显升高,钳夹状态葡萄糖利用显著降低。结论短期多不饱和脂肪酸增高可引起肝脏TG蓄积和胰岛素抵抗。     

胰岛素抵抗高血压大鼠胰岛素抵抗和血清瘦素水平对血脂的影响

用雄性Sprague-Dawley大鼠建立胰岛素抵抗高血压大鼠模型,探讨胰岛素抵抗和血清瘦素水平的变化对血脂的影响.采用高果糖饲料喂雄性Sprague-Dawley大鼠,观察其血压、胰岛素、瘦素和血脂水平的变化,用稳态模型评估胰岛素抵抗,并对上述指标进行相关性分析.结果发现,喂养8周后,与对照组相比,模型组血压、血清胰岛素和胰岛素抵抗明显升高,血清瘦素、总胆固醇和甘油三酯水平升高,高密度脂蛋白降低.模型组中,胰岛素抵抗与血压、血清瘦素和甘油三酯呈显著正相关,与高密度脂蛋白呈显著负相关;血清瘦素与血压、血清胰岛素、胰岛素抵抗和甘油三酯呈显著正相关.结果提示,高果糖饲料可诱导雄性Sprague-Dawley大鼠发生胰岛素抵抗、高血压、高瘦素血症和脂代谢紊乱,胰岛素抵抗和瘦素对脂代谢有广泛影响.     

代谢综合征患者血浆甘油三酯水平对HDL亚类分布的影响

目的探讨代谢综合征(MS)患者血浆甘油三酯(TG)水平对高密度脂蛋白(HDL)亚类分布的影响。方法选取在南华大学附属第一医院就诊的MS患者血样,全自动生化分析仪测定血脂含量及载脂蛋白浓度,根据美国国家胆固醇教育计划NCEP ATP-Ⅲ文件,将MS患者按TG浓度分4组,即TG1.69 mmol/L、1.69mmol/L≤TG2.25 mmol/L、2.25 mmol/L≤TG5.64 mmol/L、TG≥5.64 mmol/L,采用双向电泳-免疫印迹检测法测定MS患者和99例正常人血浆HDL亚类的相对含量。结果与对照组相比,MS患者血浆总胆固醇(TC)、TG、低密度脂蛋白胆固醇(LDLC)、载脂蛋白B100(Apo B100)、preβ1-HDL、HDL3b含量及Apo B100/AⅠ和LDLC/HDLC比值均显著性增高(P0.05或P0.001),HDLC、Apo AⅠ、HDL2b、HDL2a显著降低(P0.05或P0.001)。并且随着血浆TG水平的升高,小颗粒的preβ1-HDL、HDL3a和HDL3b含量升高,而大颗粒的HDL2b和HDL2a含量降低。结论MS患者HDL亚类分布异常,小颗粒的preβ1-HDL和HDL3b含量升高,而大颗粒的HDL2b和HDL2a含量降低,血浆TG含量变化可能是影响MS患者HDL亚类异常的因素之一。     

艾塞那肽对糖调节受损肥胖者血胰岛素及胰岛素抵抗的影响

目的探讨艾塞那肽对糖调节受损（IGR）肥胖者血胰岛素及血糖的影响。方法选取2011年5月至2012年11月在福建医科大学附属泉州第一医院就诊的75例糖调节受损（IGR）肥胖者为研究对象,其中62例受试者符合入选条件,按基线胰岛素水平分为高胰岛素血症（HIns,32例）与非高胰岛素血症（NHIns,30例）2组,HIns以空腹胰岛素≥15mU／L和（或）口服葡萄糖耐量试验（OGTr）2h胰岛素≥80mU儿作为切点。测定基线及应用艾塞那肽5d及14d时的空腹与OGTF2h血浆血糖、胰岛素、C肽、体重等指标。以稳态模型评估的胰岛素抵抗指数（HOMA-IR）及Gutt胰岛素敏感指数评估胰岛素抵抗及敏感性。同一组治疗前后比较采用配对t检验,组间均数比较采用单因素方差分析,率的比较采用x。检验。结果两组的空腹及OGTr2h血糖在用药5d时较基线下降（t=4．42、9．78、4．00、8．66,均P〈0．05）,HIns组空腹胰岛素在用药5d时较基线下降（t=2．07,P〈0．05）,OGTr2h胰岛素在用药5d较基线时下降,用药14d较5d时进一步下降（F=24．17,P〈0．05）。HIns组HOMA—IR在用药5d时较基线下降（t=3．27,只〈0．05）。NHIns组HOMA—IR在用药5d及14d时较基线均无下降（均P〉0．05）,HIns组Gutt胰岛素敏感指数在用药5d时较基线升高（t=-9．84,P〈0．05）,14d时较5d时进一步升高（F=55．96,P、遗0．05）。NHIns组Gutt胰岛素敏感指数在用药5d时较基线升高（t=-4．27,P〈0．05）。HIns组与NHIns组体重在5d时较基线无下降,14d时均较5d时明显下降（t=14．13、12．00,均P〈0．05）。结论IGR肥胖人群短期应用艾塞那肽即可获益调节血糖、改善胰岛素抵抗、控制体重。     

高血压家族史对人群血浆甘油三酯水平的影响

目的探讨高血压家族史对人群血浆甘油三酯水平的影响。方法在NGT375例、IGT328例、NIDDM315例人群中询问高血压家族史,测定血浆甘油三酯、血糖、胰岛素水平。测量身高、体重,分析阳性高血压家族史与血浆甘油三酯水平的关系。结果阳性高血压家族史组甘油三酯水平显著高于无高血压家族史组（1．85±0．01mmol／L,1．46±0．01mmol／L,P＜0．0001）,但年龄（55．1±0．7岁,473±0．4岁）、体重指数（27．9±0．29,25．4±0．13）、血糖水平（8．39±0．27mmol／L,7．19±0．08mmol／L）前组也显著高于后组（P＜0．001）。Pearson相关分析显示血浆甘油三酯水平与高血压家族史、年龄、性别、BMI、血糖水平、胰岛素敏感性显著相关,多因素逐步回归分析显示调整性别、胰岛素敏感性及糖耐量状态影响后,高血压家族史与血浆甘油三酯水平独立相关（P＜0．05）。结论阳性高血压家族史是高甘油三酯血症发病的危险因素,该人群是筛查高甘油三酯血症的重点。     

Influence of weight loss on plasma ghrelin responses to high-fat and high-carbohydrate test meals in obese women

BACKGROUND: Diet-induced weight loss is associated with an increase in fasting ghrelin. The influence of weight loss on postprandial ghrelin response remains discussed, but the specific response to macronutrients is not known. OBJECTIVE: The objective of the study was to assess the influence of weight loss in obese women on the plasma ghrelin response to a fat- or carbohydrate-rich meal. DESIGN: Seventeen obese women (mean body mass index 37.6 +/- 5 kg/m2) were given an energy-restricted diet (800 kcal/d) for 7 wk, followed by a maintenance diet for 1 wk. Before and after the weight reduction diet, each woman was given (in random order) two isoenergetic test meals, corresponding to 40% of daily energy needs. The test meals contained either 80% fat and 20% protein or 80% carbohydrate and 20% protein. Blood samples were collected over a 10-h period. Two-way ANOVA with repeated measures was used to assess the effect of the test meal on variables. RESULTS: Weight loss (-11.2 +/- 1.4 kg) was associated with a significant decrease in baseline plasma insulin (9.7 +/- 4.1 to 7.9 +/- 2.4 mU/ml; P < 0.0001) and leptin (25.9 +/- 8.3 to 17.2 +/- 7.8 ng/ml; P < 0.0001) and an increase in plasma ghrelin (1.86 +/- 1.05 to 2.28 +/- 1.48 ng/ml; P < 0.05). Before weight loss, there was no significant difference in postprandial ghrelin response between the test meals. After weight reduction, the ghrelin response was more pronounced after the carbohydrate test meal than after the fat test meal (P < 0.02). CONCLUSION: Weight loss is associated with an improved postprandial plasma ghrelin response to a carbohydrate meal, whereas the response to a fat meal is not modified.     

Predictors of insulin resistance in the obese with metabolic syndrome

BackgroundIn the obese, the metabolic syndrome (MetS) is assumed to reflect insulin resistance.ObjectiveTo determine the predictors of insulin resistance in obese subjects with MetS.DesignWe used the 90th percentile of the homeostasis model assessment (HOMA) to define insulin resistance in 4958 nondiabetic adults evaluated in the National Health and Nutrition Examination Surveys, 1999–2004, and compared the 373 obese subjects who were insulin-resistant (HOMA 9.52 ± 5.73) to a control group of 373 obese who had the highest sensitivity to insulin (HOMA 1.79 ± 0.44).MeasurementsMetS was present in 312 (83.6%) obese with insulin resistance and in 156 (41.8%) obese from the insulin-sensitive control group. Demographic, metabolic, and lifestyle variables were analyzed with logistic regression.ResultsIn a logistic model of insulin resistance given the presence of MetS, the significant predictors were triglycerides (P = 0.0021), body mass index (P = 0.0096), HDL-cholesterol (P = 0.0098), age (P = 0.0242) and smoking (P = 0.0366).LimitationsCross-sectional design prevents elucidation of causality for the association between insulin resistance and MetS.ConclusionsInsulin resistance is not an obligatory correlate of MetS in the obese. Its likelihood can be predicted by cigarette smoking and by the severity of obesity and dyslipidemia.     

Acute effect of exercise on plasma leptin level and insulin resistance in obese women with stable caloric intake

Obese individuals are frequently hyperleptinemic and insulin resistant. Chronic exercise is associated with improvements in plasma leptin level and insulin sensitivity; however, little is known about the acute effect of exercise on these parameters. The aim of this study was to evaluate the acute effect of aerobic exercise on plasma leptin and insulin sensitivity in obese women with stable caloric intake. Patients and Methods: Twenty-three obese women (age 41.2 +/- 10.3 years, body mass index 40.7 +/- 6.7 kg/m2) were included to the study. All subjects were admitted to an exercise program (45-minute walking sessions at 60-80% of maximum heart rate) every day except weekends for four weeks (total 20 exercise sessions). Insulin resistance was evaluated by HOMA model. Plasma glucose, insulin and leptin levels were determined at baseline and at the end of the first, seventh, and twentieth exercise session. RESULTS: Baseline and at the end of the first, seventh, and twentieth exercise session plasma leptin levels were 59.1 +/- 20.1, 58.5 +/- 21.0, 53.4 +/- 21.9, and 51.2 +/- 20.5 ng/ml and HOMA-r were 2.75 +/- 1.47, 1.77 +/- 0.71, 1.73 +/- 0.89, 1.62 +/- 0. 70, respectively. Compared to baseline, at the end of the seventh (p = 0.021) and twentieth exercise session (p = 0.003), plasma leptin levels were significantly low. Plasma leptin level did not change significantly at the end of the first exercise session (p > 0.05). At the end of the first exercise session (p = 0.005), end of the seventh (p = 0.003) and twentieth exercise session (p = 0.007) HOMA-r was lower than baseline. There was no correlation between weight loss during exercise period and the change of leptin, and HOMA-r. Fasting plasma glucose, insulin and leptin levels were determined at baseline and at the end of the first, seventh, and twentieth exercise session. CONCLUSION: Our study suggests that acute exercise decreases insulin resistance at the first exercise session with no effect on leptin levels. Significant leptin decrement was evident at the first week and lasted during the entire four weeks exercise session.     

Endocrine and metabolic effects of metformin versus ethinyl estradiol-cyproterone acetate in obese women with polycystic ovary syndrome: a randomized study

Metformin, a biguanide antihyperglycemic drug, has been shown to improve ovarian function and glucose metabolism in women with polycystic ovary syndrome (PCOS), but results concerning its effects on insulin sensitivity are controversial. Oral contraceptive pills are commonly used in the treatment of PCOS; but, like metformin, their influence on insulin sensitivity is not well known. We randomized 32 obese (body mass index > 27 kg/m2) women with PCOS, either to metformin (500 mg x 2 daily for 3 months, then 1,000 mg x 2 daily for 3 months) or to ethinyl estradiol (35 microg)-cyproterone acetate (2 mg) oral contraceptive pills (Diane Nova) for 6 months. Metformin significantly decreased the waist-to-hip ratio, serum testosterone, fasting free fatty acid, and insulin concentrations and improved oxidative glucose utilization and menstrual cyclicity, with slight (but nonsignificant) improvements in insulin hepatic extraction and insulin sensitivity. Diane Nova significantly decreased serum testosterone and increased serum sex hormone-binding globulin concentrations and glucose area under the curve during oral glucose tolerance test. It is concluded that metformin, probably by way of its effect on adipose tissue, leads to reduction of hyperinsulinemia and concomitant improvement in the menstrual pattern; and therefore, it offers a useful alternative treatment for obese, anovulatory women with PCOS. Despite slight worsening of glucose tolerance, Diane Nova is an efficient treatment for women with hyperandrogenism and hirsutism.     

Effect of insulin on plasma norepinephrine and 3,4-dihydroxyphenylalanine in obese men

Increasing evidence relates serum insulin level and blood pressure in obese individuals. Although the connection between these two factors is not established, a common presumption is that the sympathetic nervous system is somehow involved, in part, because laboratory studies demonstrate insulin stimulation of sympathetic and cardiovascular activity. Because the obese may exhibit altered responsiveness to insulin action, the current investigation compared cardiovascular and neurohumoral responses to euglycemic insulin infusion (200 mU/m2/min) in obese and lean men. At baseline, obese men displayed higher glucose and insulin levels, faster pulse rates, and elevated mean arterial pressures (MAP) than lean controls; plasma norepinephrine (NE) and 3,4-dihydroxyphenylalanine (DOPA) concentrations, however, did not differ. During insulin infusion, pulse rate increased equally in obese and lean subjects (from 69 to 78 min-1 in obese and from 56 to 66 min-1 in lean subjects), while MAP remained unchanged in both groups. Elevations in plasma NE (+85 pg/mL in obese and +109 in lean pg/mL) and reductions in plasma DOPA (-233 pg/mL in obese and -376 pg/mL in lean) did not differ between groups. Sodium excretory rate decreased during insulin infusion in lean subjects by 2.2 mEq/h but increased in obese by 5.3 mEq/h (difference in response between groups, P = .024). Thus, in these obese men, cardiovascular and sympathetic responses to insulin persist despite evidence of moderate insulin resistance; increased sympathetic activity, as a cause for the resting tachycardia and borderline hypertension at baseline, seems unlikely.     

The influence of fitness on insulin resistance in obese children

An increasingly pervasive environment of reduced activity and easy access to high caloric food is leading to an epidemic of poor cardiovascular fitness, obesity, insulin resistance and type 2 diabetes (T2DM) in children. Studies have shown that insulin resistance (IR) to be an independent predictor for morbidity as well as mortality. These serve as a strong stimulus for public health strategies to improve fitness in children and adolescents. Methods to assess IR, improve IR and understand complications are increasingly important in children.     

Relation among the plasma triglyceride/high-density lipoprotein cholesterol concentration ratio, insulin resistance, and associated cardio-metabolic risk factors in men and women

Results of recent studies using the ratio of plasma triglyceride (TG) to high-density lipoprotein (HDL) cholesterol concentration to identify insulin-resistant patients at increased cardiometabolic risk have emphasized that the cut point used for this purpose will vary with race. Because TG and HDL cholesterol concentrations vary with gender, this analysis was initiated to define gender-specific plasma TG/HDL cholesterol concentration ratios that best identified high-risk subjects among women (n = 1,102) and men (n = 464) of primarily European ancestry. Insulin resistance was defined as the 25% of the population with the highest values for fasting plasma insulin concentration and homeostasis model assessment of insulin resistance. Using TG/HDL concentration ratios >2.5 in women and >3.5 in men identified subgroups of men and women that were comparable in terms of insulin resistance and associated cardiometabolic risk, with significantly higher values for fasting plasma insulin, homeostasis model assessment of insulin resistance, blood pressure, body mass index, waist circumference, and glucose and TG concentrations and lower HDL cholesterol concentrations than in women and men below these cut points. The sensitivity and specificity of these gender-specific cut points to identify insulin-resistant subjects were about 40% and about 80%, respectively. In conclusion, the plasma TG/HDL cholesterol concentration ratio that identifies patients who are insulin resistant and at significantly greater cardiometabolic risk varies between men and women.     

Endocrine, metabolic and cardioprotective effects of hexarelin in obese Zucker rats

Genetically obese male Zucker rats have an impaired secretion of GH, coupled to hyperinsulinemia, hyperlipidemia and glucose intolerance. The aim of this study was to evaluate whether a chronic treatment with hexarelin, a synthetic enkephalin-derived hexapeptide with a potent GH-releasing activity, might be able to ameliorate the somatotropic function and reverse some metabolic alterations associated with obesity in male obese Zucker rats. Furthermore, as decreased GH secretion and insulin resistance are associated with increased cardiovascular risk, we also tested the capacity of hexarelin to prevent postischemic ventricular dysfunction in hearts of male obese Zucker rats. Obese and lean male rats of the Zucker strain were treated with hexarelin (80 microgram/kg, b.i.d., s.c.) or saline (1 ml/kg, b.i.d., s.c.) for 30 days. An acute hexarelin injection (80 microgram, s.c.) at the 28th day of treatment elicited a rise in plasma GH levels in ! lean but not in obese rats (pretreated or not with hexarelin); lean rats chronically treated with hexarelin showed a greater increase in plasma GH as compared with control counterparts. At the end of the experiment, pituitary GH mRNA levels were significantly reduced in obese rats and hexarelin administration failed to increase pituitary GH mRNA and IGF-I concentrations in plasma and heart. Chronic treatment with hexarelin increased insulinemia and blood glucose levels in obese but not in lean rats, left unaltered the high triglyceride levels but significantly decreased plasma cholesterol concentrations in obese rats. Heart preparations from lean and obese Zucker rats treated with saline, subjected to low flow ischemia and reperfusion, showed at reperfusion: a) a low recovery of postischemic left ventricular developed pressure (LVDP), coupled to a substantial increase in coronary perfusion pressure, and b) a marked increase in creatine kinase released in the perfusates. Hexare! lin administration for 30 days counteracted the heart ischemic damage both in lean and obese Zucker rats. In fact, the recovery of LVDP at reperfusion was significantly higher than in controls and the increase in coronary resistance was minimal. Collectively, these data indicate that a 30-day treatment with hexarelin was unable to improve somatotropic function in male obese Zucker rats but was successful in decreasing plasma cholesterol concentrations. Hexarelin exerted a cardioprotective effect in both lean and obese rats. The heart-protective activity afforded by the peptide was divorced from any stimulation of the GH axis and is probably exerted through activation of specific cardiac receptors.