Defining and Predicting Complete Remission of Type 2 Diabetes: A Short-Term Efficacy Study of Open Gastric Bypass

ObjectiveTo investigate the metabolic effects of open Roux-en Y gastric bypass (RYGB) on pancreatic endocrine reserve in overweight/obese Chinese patients with type 2 diabetes during postoperative year 1.MethodsRetrospective analysis comparing pre- and postoperative results of oral glucose tolerance tests (OGTT) with determinations of insulin and C-peptide, glycated hemoglobin (HbA1c), insulin resistance (HOMA-IR), and BMI at 1, 3, 6, and 12 months in 99 overweight patients (BMI 26.3 ± 4.0 kg/m²; 59 men) with type 2 diabetes at the General Hospital of Chengdu Military Region.Results79 patients (80%) achieved complete remission (maintaining random blood glucose levels < 11.1 mmol/l, fasting blood glucose levels < 7.0 mmol/l, 2-hour OGTT blood glucose levels < 11.1 mmol/l, and glycated hemoglobin < 6.5%). Nine cases (9%) were ‘improved’ (reduced medication or diet controlled blood sugar), and 11 cases did not meet either criterion (‘unchanged’). Patients in complete remission were younger and heavier, more often men, had significantly shorter history of diabetes (4.3 ± 3.8 years vs. 7.6 ± 3.8 years, p < 0.05), and exhibited significantly higher fasting and OGTT levels of C-peptide and insulin, and HOMA-IR than the other 2 groups (p < 0.05-0.01).ConclusionOpen gastric bypass achieved complete remission of type 2 diabetes in Chinese overweight/obese, heavier, younger, predominantly male patients with shorter duration of disease exhibiting greater pancreatic endocrine reserve.Key Words: Diabetes, Gastric bypass, Pancreatic function, Remission, Obesity     

Impaired Secretion of Total Glucagon-like Peptide-1 in People with Impaired Fasting Glucose Combined Impaired Glucose Tolerance

Objective: We assessed the serum glucagon-like peptide-1 (GLP-1) levels for Chinese adults with pre-diabetes (PD) and newly-diagnosed diabetes mellitus (NDDM) during oral glucose tolerance test (OGTT). The relationships between total GLP-1 level and islet β cell function, insulin resistance (IR) and insulin sensitivity (IS) were also investigated.Methods: A 75g glucose OGTT was given to 531 subjects. Based on the results, they were divided into groups of normal glucose tolerance (NGT), isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), IFG combined IGT (IFG+IGT) and NDDM. Total GLP-1 levels were measured at 0- and 2-hour during OGTT. Homeostasis model assessment of β cell function (HOMA-β), HOMA of insulin resistance (HOMA-IR), Gutt and Matsuda indexes were calculated. The relationships between GLP-1 level and β cell function, IR and IS were analyzed.Results: The levels of total fasting GLP-1 (FGLP-1), 2h GLP-1 (2hGLP-1) and 2hGLP-1 increments (∆GLP-1) following OGTT reduced significantly in IFG+IGT and NDDM groups (P<0.005). HOMA-β , HOMA-IR, Gutt and Matsuda indexes demonstrated various patterns among NGT, isolated IFG, isolated IGT, IFG+IGT and NDDM groups (P<0.05). Spearman rank correlation analysis and multivariable linear regression model suggested that some levels of correlation between GLP-1 levels, ∆GLP-1 and β cell function, IR (P<0.05).Conclusions: The total GLP-1 levels and its response to glucose load decreased significantly in IFG+IGT group, compared to isolated IFG or IGT group. They were even similar to that of NDDM group. Moreover, there were observable correlations between impaired GLP-1 secretion and β cell function, IR and IS.     

Anti-Hyperglycemic and Anti-Hyperlipidemic Potential of a Polyherbal Preparation “Diabegon” in Metabolic Syndrome Subject with Type 2 Diabetes

Background

In the present study, “Diabegon” a poly-herbal preparation, with hypoglycemic activity, was evaluated for its preventive effect in metabolic syndrome subjects with type 2 diabetes and also to reveal its side effects, on liver and kidney.

Materials and Methods

Type 2 diabetic subjects with metabolic syndrome (N=58) were categorized on the basis of age and fasting blood glucose. The grouping was as follows: Group I (35–50 yrs), Group II (51–65 yrs), Group III >65 yrs, Group IV FBS<145.9, Group V FBS>145. Each group was administered 4 gm of diabegon daily. Blood glucose levels, lipid profile, liver and kidney function of the subjects were regularly monitored within 3 months of interval to 18 months.

Results

The reduction in fasting blood glucose level ranged from 12.3% (P<0.05) to 42% (P<0.001) after 18 month of therapy whereas in postprandial blood glucose, the decrease ranged from 28% (P<0.05) to 32% (P<0.05) after 18 month of therapy. Overall reductions in the individual parameters of the metabolic syndrome subjects were significantly higher in Group I. Cholesterol level decreased from 11% to 27.2% (P<0.001), triglyceride levels decreased from 24% to 55%, VLDL and LDL levels reduced by 60% & 54% respectively after 18 months of therapy. The HDL-C level increased in all groups. Moreover, diabegon administration for 1.5 years exhibited no alteration in liver and kidney function tests, which indicate its non-toxicity.

Conclusion

Our study suggests that diabegon could be included as a preventive treatment in metabolic syndrome subjects with type 2 diabetes especially for long term treatment as it efficiently shows anti-hyperglycemic and anti-lipidemic effects with no adverse impacts on the liver and kidney.     

Association between osteoporosis and hepatitis B cirrhosis: a case-control study

Background and aimsHepatitis B virus (HBV)-related cirrhosis is associated with decreased bone mineral density (BMD); however, the mechanism is yet unknown. To assess the incidence of osteoporosis in patients with HBV-associated cirrhosis and relevant mechanisms.MethodsA total of 80 hospitalized patients with HBV-associated cirrhosis and 80 healthy controls were enrolled. The levels of serum osteocalcin, total procollagen type 1 amino-terminal propeptide, β-C-terminal telopeptide of type I collagen (β-CTX), and 25-hydroxy vitamin D3 (25(OH)D3) was evaluated in the cirrhosis group.ResultsThe BMDs of the lumbar spine (P<0.001) and hip joints (P=0.015) in the cirrhosis group were significantly lower than those in the controls. The incidence of osteoporosis in the cirrhosis group was significantly higher than that in the control group (P<0.001). Compared to the patients of the Child-Pugh grade A and B, the BMD of lumbar spine and 25(OH)D3 was significantly decreased in patients of grade C, while β-CTX was elevated. Patients in the cirrhosis group faced a higher risk of osteoporosis as compared to the controls(P<0.001).ConclusionsEnhanced bone resorption accounted for increased risk of osteoporosis in severe cirrhosis. Thus, HBV-associated cirrhosis was a risk factor for osteoporosis.     

Influence of muscle mass and work on post-exercise glucose and insulin responses in young untrained subjects

The 18 h post-exercise glucose and insulin responses of six male and six female subjects were measured following one- or two-leg cycling to determine the influence of muscle mass involvement and work. Each subject performed three exercise trials on a Cybex Met 100 cycle ergometer: (1) two-leg exercise for 30 min at 60% of the two-leg VO _{2 max}; (2) one-leg exercise for 30 min at 60% of one-leg VO _{2 max}; and (3) one-leg exercise (one-legTW) at 60% of the one-leg VO _{2 max} with the total work performed equal to that of the two-leg trial (duration ≈50 min). These trials were preceded by 2 days of inactivity and followed by an 18 h post-exercise 75 g oral glucose tolerance test (OGTT). The glucose response during the baseline OGTT demonstrated that the subjects had normal glucose tolerance with fasting serum glucose levels of 5.1 mM , and 1 and 2 h serum glucose less than 7.8 mM , respectively. The 18 h post-exercise glucose responses were significantly lower following the two-leg trial (P < 0.05), with the area under the curve values being 129.9 mM h^?1 less than the resting control level. The 18 h post-exercise insulin AUC response of the two-leg trial was significantly lower than either of the one-leg responses (14.7 pM below the one-leg and 5.0 pM below the one-leg TW) but was not associated with a change in C-peptide. The 18 h post-exercise insulin levels of the one-leg and one-legTW trials were above or near the resting control values, but were not accompanied by a significant change in C-peptide. In conclusion, the data presented here show that the amount of muscle tissue utilized during an exercise bout can influence both the glucose and insulin responses, whereas the amount of total work employed during the exercise had no effect on either of these parameters.     

幽门螺杆菌感染与轻度颈动脉狭窄患者OGTT水平的关联分析

目的 分析幽门螺杆菌感染与轻度颈动脉狭窄患者OGTT水平的关联.方法 选取颈动脉轻度狭窄患者105例,根据感染情况分为幽门螺杆菌感染组和非幽门螺杆菌感染组.分析幽门螺杆菌感染与轻度颈动脉狭窄患者OGTT水平的关联,应用SPSS 20.0进行分析.结果 OGTT实验中2组患者摄入葡萄糖后0.5h血糖水平达到最高峰值,然后开始下降,摄入葡萄糖后1h的血糖水平感染组显著高于非感染组(P＜0.05).胰岛素水平也是空腹水平较低,在摄入葡萄糖后0.5h水平达到最高峰值,然后开始下降,2组在5个时间点的胰岛素水平差异均有统计学意义(P＜0.05).C肽水平也是空腹水平较低,在摄入葡萄糖后0.5h水平达到最高峰值后下降.比较2组患者OGIT检测结果中的C肽水平在空腹状态下差别无统计学意义,摄人葡萄糖后检测的4个时间点差异均有统计学意义(P＜0.05).结论 Hp感染的患者糖代谢开始1h左右血糖水平与无Hp感染者的情况差别有统计学意义.在Hp感染的患者基础胰岛素水平值就较高,随着摄人葡萄糖以及糖代谢的开始,始终存在胰岛素水平高于无Hp感染者的情况.Hp感染的患者基础C肽水平值与非感染患者相当,随着摄人葡萄糖以及糖代谢的开始,始终存在C肽水平高于无Hp感染者的情况.     

Hemoglobin A1c Can Identify More Cardiovascular and Metabolic Risk Profile in OGTT-Negative Chinese Population

Objective: To investigate the significance of hemoglobin A1c (HbA1c) in cardiovascular and metabolic risk stratification among diabetes and non-diabetes in southern Chinese.Methods: Indigenous adults (aged more than or equal to 35 years) without known diabetes were enrolled in the cross-sectional survey. According to oral glucose tolerance test (OGTT), participants were categorized into OGTT-negative group and OGTT-positive group. Cardiovascular and metabolic risk profile was compared between different HbA1c levels (≥ 6.5% vs. < 6.5%) in each group.Results: The prevalence of OGTT-diagnosed diabetes was 6.45% (422/6540). In OGTT-negative group, subjects with HbA1c ≥ 6.5% were older, had higher prevalence of coronary heart disease, current smoking, hypertension, obesity and abdominal obesity. They also had higher body weight, waist-hip ratio, body mass index, glucose levels (fasting plasma glucose, 2-hour plasma glucose and HbA1c), and lipid levels (total cholesterol and low density lipoprotein cholesterol). In OGTT-positive group, patients with HbA1c ≥ 6.5% identified less cardiovascular and metabolic risk file than that in OGTT-negative group.Conclusions: Subjects with HbA1c ≥ 6.5% have more unfavorable cardiovascular and metabolic risk profile than those with HbA1c < 6.5%, especially in OGTT-negative population. More attention should be paid to this subgroup in clinical practice.     

Effects of 4 Weeks Recombinant Human Growth Hormone Administration on Insulin Resistance of Skeletal Muscle in Rats

Purpose

Effect of recombinant human growth hormone (rhGH) administration on lipid storage, and its subsequent effect on insulin sensitivity have not yet been adequately examined. Thus, we investigated the effects of rhGH treatment on muscle triglyceride (TG) and ceramide content, and insulin sensitivity after 4 weeks of rhGH administration in rats.

Materials and Methods

Fourteen rats were randomly assigned to two groups: rhGH injection group (GH, n = 7) and saline injection group (CON, n = 7). GH received rhGH by subcutaneous injections (130 µg·kg^-1·day^-1, 6 days·week^-1) for 4 weeks, while CON received saline injections that were equivalent in volume to GH group. Intramuscular TG and ceramide content and hepatic TG content were measured. To determine insulin sesitivity, oral glucose tolerance test (OGTT) and muscle incubation for glucose transport rate were performed in rats, and used as indicators of insulin sensitivity. We also examined plasm lipid profiles.

Results

After 4 weeks of rhGH treatment, the GH group had higher muscle and liver TG contents than the CON (p < 0.05). Ceramide content in GH was significantly greater than that in CON (p < 0.05). GH also had higher plasma levels of FFA (p < 0.05), glucose and insulin responses during OGTT (p < 0.05), and lower glucose transport rates in submaximal insulin concentration (p < 0.05) as compared with CON. Results indicate that rhGH treatment is associated with insulin resistance in rats.

Conclusion

rhGH treatment elevated muscle TG and ceramide content, and hepatic TG content. Thus, elevation of these compounde by rhGH treatment could contribute to the development of insulin resistance in rats.     

The way of serum chromium utilization may contribute to cardiovascular risk factors in centrally obese persons

Introduction

Obesity-related disturbances are considered to be risk factors for cardiovascular disease (CVD). Chromium is shown to improve carbohydrate and lipid metabolism. Conflicting data on effects of chromium supplementation in humans are published. The aim of the study was to assess the concentrations of serum chromium during the 75-g oral glucose tolerance test (OGTT) in obese persons.

Material and methods

Fourty-eight centrally obese Caucasians, apparently healthy, using neither special diet nor mineral supplementation, were enrolled in the study. During the OGTT, 0-min and 120-min concentrations of plasma glucose (G 0’, G 120’), serum insulin (Ins 0’, Ins 120’) and chromium (Cr 0’, Cr 120’) were determined. Plasma lipids, apolipoproteins A and B, and serum uric acid were measured at 0 min only. For parameters assessed during the OGTT, the difference D = [(120’ concentration) – (0’ concentration)] was calculated. Contradictory tendencies of Cr 120’ were observed; thus the difference of serum chromium concentrations, DCr = [(Cr 120’) – (Cr 0’)], was used to establish the positive DCr group with DCr > 0 (PosDCr: n= 24; 9 male/15 female) and the negative DCr group with DCr < 0 (NegDCr: n= 24; 8 male/16 female).

Results

The studied groups were comparable as far as their metabolic parameters are concerned, except higher G 120’ (p= 0.043) and DG (p = 0.048), and lower Cr 120’ (p < 0.000), which were observed in the NegDCr group. The NegDCr persons showed inverse correlations between Cr 0’ and systolic and diastolic blood pressure.

Conclusions

We suggest that the studied centrally obese persons differed in chromium metabolism. In subjects “consuming” Cr during the OGTT, chromium status may be associated with increased risk for CVD.     

Insulin binding to erythrocytes in hyperinsulinemic patients with precirrhotic hemochromatosis and cirrhosis

Summary This study investigated insulin receptor binding (number and affinity) to erythrocytes in patients with precirrhotic hemochromatosis, patients with cirrhosis, and healthy subjects. To evaluate plasma glucose and insulin levels, an oral glucose tolerance test (OGTT) was performed in all subjects. In the fasting state, all patients exhibited normal glucose levels. Precirrhotic patients showed slight impairment of glucose tolerance while cirrhotic patients were strikingly glucose intolerant. In both patient groups, fasting plasma insulin levels were increased. Following the glucose load, plasma insulin levels were significantly enhanced in precirrhotic patients at 90 and 120 min and increased at all times in cirrhotic patients. In the postabsorptive state (in the presence of hyperinsulinemia) insulin binding and the number and affinity of insulin receptors of erythrocytes were not different in precirrhotic or cirrhotic patients when compared to controls. We conclude that studies of insulin binding on erythrocytes do not contribute to the evaluation of the pathogenesis of insulin resistance in liver disease.Abbreviations K_a affinity constant - OGTT oral glucose tolerance test - R₀ receptor number This work was presented in part at the annual meeting of the German Association for the Study of the Liver, Göttingen, FRG, January 1986, and at the annual meeting of the Deutsche Gesellschaft für Innere Medizin, Wiesbaden, FRG, April 1986     

Association of glycosylated hemoglobin (HbA1c) levels with Iinsulin resistance in obese children

Objectives

We investigated the relationship between insulin resistance reflected by homeostasis model assessment (HOMA-IR) index and serum HbA1c levels of obese children.

Material and Methods

This study included 70 obese and 60 normal weight healthy children between the ages of 3 and 15. Anthropometric measures and biochemical tests (fasting glucose, fasting insulin, HbA1c) were performed on all subjects. Plasma glucose levels were measured by the glucose oxidase method. Plasma insulin concentrations were measured by radioimmunoassay (RIA). HOMA-IR index was used to estimate insulin resistance. A cut-off HOMA-IR level of ≥2.5 was accepted. The HbA1c analysis was performed using high-pressure liquid chromatography. The statistical analysis was performed using SPSS 5. Student''s unpaired t-test and the Mann-Whitney U test were used to determine statistical significance.

Results

Gender distribution did not reveal significant difference among the obese (F: 48.6%, M: 51.4%) and the non-obese (F: 46.7%, M: 53.3%) groups. The mean age value was significantly higher in the obese group (10.09± 3.09) (p>0.005) than the non-obese group (8.31±3.14) (p<0.05). The mean value of body mass index (BMI) was 25.55±4.3 in the obese group and 16.63±2.3 in the non-obese group. The mean HOMA-IR values of obese group (2.84±1.77) was significantly higher than the non-obese group (1.50±0.95) (p<0.005). Insulin resistance was significantly higher in the obese group. Subjects with HOMA-IR ≥2.5 levels in the obese group had significantly higher HbA1c values than those with HOMA-IR <2.5 levels.

Conclusions

High HbA1c levels in obese children can be used as a screening tool to detect insulin sensitivity and resistance at an early stage.     

心理应激对Ⅱ型糖尿病人糖代谢影响的对照研究

应激与Ⅱ型糖尿病人糖代谢之间的关系研究已经进行多年,尤其近十五年有了相当多的文献报道。如Ｇｒａｎｔ等研究发现急性生活事件尤其是急性负性生活事件与糖尿病人症状的加重有关。ＭｃＣｌｅｓｋｙ等发现糖尿病人表现出对手术应激的高血糖反应。但ＮａｌｉｂｏｆｆＣｏｈｅｍ等人的研究结果显示尽管躯体性应激(姿势限制、夹手)和心理性应激(心算)使血浆儿茶酚胺水平升高,但两组病人的血糖水平并无显著改变[1]。可见,应激对糖尿病人糖代谢的影响尚未能得出一确切的结论。以往的研究大多缺乏糖尿病人的对照组,而且研究的结果易受病情、饮食…     

Effects of twice-daily injections of premixed insulin analog on glycemic control in type 2 diabetic patients

Purpose

Premixed insulin is effective to improve glycemic control; however, clinicians may be less likely to know which premixed insulin is appropriate for which patients. This study aimed to evaluate the effects of twice-daily injections of premixed insulin lispro on glycemic control in type 2 diabetic patients.

Materials and Methods

Forty type 2 diabetic patients, who had been treated with twice-daily injections of human protamine mixture 30/70 insulin for at least 12 months, were divided into two groups; one group whose blood glucose 2 hours after breakfast was greater than 200 mg/dL, was switched to lispro mix50, and the other group whose blood glucose 2 hours after breakfast < 200 was switched to lispro mix25.

Results

Glycated haemoglobin (HbA1c) significantly improved in the Mix50 group from 8.3% to 7.5% (at 12 weeks; p < 0.05), and to 7.5% (at 24 weeks; p < 0.05). On the other hand, HbA1c levels in the Mix25 group were slightly decreased from 8.1% to 7.7% at 12 weeks (p < 0.05), and to 7.9% at 24 weeks (not significant). Both postprandial plasma glucose and fasting plasma glucose levels were significantly improved in the Mix50 group, but not in the Mix25 group. Overall, 95% of subjects preferred premixed lispro insulin from human insulin in the viewpoint of the timing of insulin injection by questionnaire analysis.

Conclusion

Switching from human protamine mixture 30/70 insulin to lispro mix50 twice-daily injection therapy in patients with high postprandial plasma glucose could improve their glycemic control and quality of life.     

Plasma androgens and oestradiol during oral glucose tolerance test in patients with polycystic ovaries

Hyperinsulinaemia is common patients with polycystic ovaries (PCO), and a relationship between hyperinsulinaemia and hyperandrogenaemia has been suggested. We studied the effect of increased circulating insulin in response to an oral glucose tolerance test (OGTT) on plasma levels of androgens and oestradiol in PCO patients and in healthy control subjects. A 75 g, 3 h oral glucose tolerance test (OGTT) was performed in eight non-obese and seven obese PCO patients, and in 10 non-obese control subjects. An additional group of five women were fasting during the study period. The increase in insulin concentration was higher in obese and non-obese PCO patients than in non-obese control subjects, and the peak values were observed at 30 or 60 min. In the fasting control subjects, the mean concentration of androstenedione decreased slightly due to a diurnal variation. During the OGTT, mean concentrations of androstenedione decreased in all groups at 30 min, after which a slight increase was observed in PCO patients and a plateau in control subjects. Similarly, mean testosterone increased after an initial decrease in obese PCO patients whereas no change was found in non-obese PCO patients. No statistically significant differences were found in the responses of androstenedione or testosterone levels to OGTT in obese or non-obese PCO patients compared to normals. No significant responses of plasma oestradiol levels to OGTT were found. These findings failed to demonstrate any significantly abnormal acute androgen responses to OGTT-stimulated hyperinsulinaemia in PCO patients, but did not exclude possible long-term effects of hyperinsulinaemia.     

Inflammatory cytokines and plasma redox status responses in hypertensive subjects after heat exposure

Hypertension is characterized by a pro-inflammatory status, including redox imbalance and increased levels of pro-inflammatory cytokines, which may be exacerbated after heat exposure. However, the effects of heat exposure, specifically in individuals with inflammatory chronic diseases such as hypertension, are complex and not well understood. This study compared the effects of heat exposure on plasma cytokine levels and redox status parameters in 8 hypertensive (H) and 8 normotensive (N) subjects (age: 46.5±1.3 and 45.6±1.4 years old, body mass index: 25.8±0.8 and 25.6±0.6 kg/m², mean arterial pressure: 98.0±2.8 and 86.0±2.3 mmHg, respectively). They remained at rest in a sitting position for 10 min in a thermoneutral environment (22°C) followed by 30 min in a heated environmental chamber (38°C and 60% relative humidity). Blood samples were collected before and after heat exposure. Plasma cytokine levels were measured using sandwich ELISA kits. Plasma redox status was determined by thiobarbituric acid reactive substances (TBARS) levels and ferric reducing ability of plasma (FRAP). Hypertensive subjects showed higher plasma levels of IL-10 at baseline (P<0.05), although levels of this cytokine were similar between groups after heat exposure. Moreover, after heat exposure, hypertensive individuals showed higher plasma levels of soluble TNF receptor (sTNFR1) and lower TBARS (P<0.01) and FRAP (P<0.05) levels. Controlled hypertensive subjects, who use angiotensin-converting-enzyme inhibitor (ACE inhibitors), present an anti-inflammatory status and balanced redox status. Nevertheless, exposure to a heat stress condition seems to cause an imbalance in the redox status and an unregulated inflammatory response.     

原发性高血压患者糖负荷后血糖和胰岛素变化对游离脂肪酸水平的影响

目的:探讨糖负荷后血糖和胰岛素变化对血清游离脂肪酸(FFA)水平的影响。方法: 234例高血压病患者[2型糖尿病(DM)20例,糖耐量低减(IGT)74例,正常糖耐量(NGT)140例;男98例,女136例]做口服葡萄糖耐量试验(OGTT),测定0、30、60、120 min时相的葡萄糖、血清胰岛素和FFA水平。结果: 空腹血清FFA浓度(μmol/L):DM组(1 048.7±481.6)显著高于IGT组(706.1±332.1)(P＜0.05)和NGT组(725.8±353.9)(P＜0.05)。DM组OGTT血糖水平显著升高,胰岛素释放曲线呈反应低平,高峰不明显或呈延迟相。3组FFA释放均呈低下,DM组更为显著。30、60、120 min时相的血清FFA水平,3组均无显著差异。结论: 糖尿病患者空腹血清FFA水平升高,OGTT中糖尿病患者胰岛素分泌的绝对不足未能增大DM组FFA水平与IGT及NGT组的差异,相反缩小了与IGT和NGT组的差距,提示体内葡萄糖利用水平对血清FFA浓度可能有重要的影响。     

Insulin and C-peptide secretory responses to glucagon in man: studies on the dose-response relationships

The present study investigated the insulin and C-peptide secretory responses to glucagon in non-diabetic humans. Glucagon induced a transient increase in plasma insulin and C-peptide concentrations. At the dose level of 0.5 mg, glucagon elicited more efficient responses than at the dose level of 0.25 mg (p less than 0.05). However, the responses were not further potentiated by glucagon at 1.0 mg. Plasma glucose levels did not change during the first 2 min after glucagon injection, when already a marked increase in plasma insulin and C-peptide levels were observed. Thereafter, however, plasma glucose levels increased, to be maximal at 20 min after glucagon injection. Calculations of the minute-to-minute increase of plasma insulin and C-peptide levels revealed that plasma insulin levels increased by 32 +/- 7% of the increase in plasma C-peptide levels during the first 2 min, and by 36 +/- 6% of the increase in plasma C-peptide levels during the 3rd and 4th min after injection; the difference being the liver extraction of insulin. We conclude from this study in man that glucagon stimulates insulin secretion through both direct and indirect effects, that following glucagon injection, approximately 65% of the secreted insulin is extracted by the liver, and that the dose level of 0.5 mg glucagon is the optimal dose level for the stimulation of insulin secretion.     

Circulating visfatin level and visfatin/insulin ratio in obese women with metabolic syndrome

Introduction

Visfatin is an adipokine secreted by visceral adipose tissue with insulin-mimetic properties. Higher circulating visfatin levels were reported in type 2 diabetes. The aim of this study was to analyse circulating visfatin and insulin levels and the visfatin/insulin ratio in obese women with and without metabolic syndrome (MetS).

Material and methods

The study involved 92 obese women. Subjects were diagnosed with MetS according to IDF 2005 criteria. The MetS group consisted of 71 subjects (age: 52.8 ±9.4 years, body mass index [BMI]: 39.1 ±5.6 kg/m², waist circumference: 109.6 ±11.4 cm and fat mass: 52.0 ±12.8 kg) while the non-MetS group consisted of 21 subjects (age: 51.7 ±9.5 years, BMI: 36.3 ±5.2 kg/m², waist circumference: 104.7 ±11.0 cm and fat mass: 45.2 ±10.7 kg). In addition to anthropometric measurements and assessment of serum glucose and lipids, plasma concentrations of visfatin were estimated by enzyme-linked immunosorbent assay (ELISA) and of insulin by radioimmunoassay (RIA). Homeostatic model assessment insulin resistance (HOMA-IR) and visfatin/insulin ratio were calculated.

Results

In the MetS group significantly higher (p < 0.01) plasma concentrations of insulin and HOMA-IR values but similar visfatin levels were observed than in the non-MetS group. As a consequence of the significantly higher plasma insulin concentration the visfatin/insulin ratio was significantly lower in the MetS group (p < 0.05). The visfatin/insulin ratio correlated inversely with anthropometric parameters such as body mass, BMI, body fat and waist circumference (r = –0.41, p = 0.0003; r = –0.42, p = 0.0002; r = –0.29, p = 0.01; r = –0.23, p = 0.04, respectively).

Conclusions

We conclude that the visfatin/insulin ratio declining with increasing visceral obesity may predispose to the development of insulin resistance.