The effect of metformin on expression of vaspin mRNA in insulin resistant rats induced by high-fat diet / 中华内分泌代谢杂志

High-fat diet-induced insulin resistance rat model was assessed by euglycemic-hyperinsulinemic clamp technique.Compared with the control group,the vaspin mRNA expression in adipose tissue was significantly decreased in insulin resistant rats induced by high-fat diet( P＜0.05 ),which was increased by metformin( P＜0.05 ).These data indicate that metformin may ameliorate insulin resistance in rats via upregulating vaspin mRNA expression.

Effects of short-term continuous subcutaneous insulin infusion on fasting plasma vaspin levels in patients with recent-onset type 2 diabetes mellitus / 中华内分泌代谢杂志

Objective To investigate the effects of short-term continuous subcutaneous insulin infusion (CSII) on plasma visceral adipose tissue-derived serine protease inhibitor ( vaspin ) levels in patients with recentonset type 2 diabetes mellitus, and to study the association between insulin sensitivity and vaspin levels.Methods Thirty patients with recent-onset type 2 diabetes mellitus were treated with CSII for 2 weeks.Euglycemic-hyperinsulinemic clamps (EHC) were performed to evaluate the insulin sensitivity in type 2 diabetes group. Plasma vaspin levels were measured by an ELISA kit. The association between plasma vaspin levels and metabolic parameters were analyzed. Results Fasting plasma vaspin levels were higher in type 2 diabetes than in impaired glucose regulation and normal glucose tolerance groups [( 1.83±0.55 vs 0. 43±0.21 and 0.56±0.26) ng/ml,P＜0.05]. With CSII,vaspin levels [( 1.19 ±0.57 vs 1.83 ±0.55 ) ng/ml, P＜0.05] and homeostasis model assessment for insulin resistance [HOMA-IR ,2.30 ( 1.09-7.2 ) vs 4.28 ( 1.7-6.47 ), P＜0.05] were significantly decreased,accompanied with an increase in glucose metabolic rate [(5. 10±0.51 vs 2.99±0.42 )mg·kg-1·min-1 ,P＜0.05] in type 2 diabetes group. Changes in circulating vaspin concentrations were correlated positively with changes in HOMA-IR. Conclusion In type 2 diabetic patients,elevated plasma vaspin levels are significantly decreased after CSII treatment. Vaspin may play a role in improving insulin sensitivity of diabetic humans.

Evaluation of insulin resistance in type 1 diabetes with euglycemic-hyperinsulinemic clamp / 中华内科杂志

Objective To investigate insulin resistance in type 1 diabetes(T1DM)with euglycemic-hyperinsulinemic clamp.Methods Eight cases of newly diagnosed T1DM and 8 cases of newly diagnosed type 2 diabetes(T2DM)were selected.Their insulin sensitivity index(ISI)was evaluated with euglycemic-hyperinsulinemic clamp after 2 week insulin intensive treatment and compared with that of 10 heMthy volunteers(normal control group,NC group).Results Age,BMI,fasting insulin(Fins),fasting C-peptide in the TI DM group were significantly lower than those in the NC group.while waist-to-hip ratio (WHR),systolic blood pressure(SBP),diastolic blood pressure(DBP),TC,TG,LDL-C,HDL-C were not significantly different between the T1DM and NC groups.Age,BMI,WHR,Fins,fasting C-peptide,SBP,TC,TG in the T1DM group were significantly lower than those in the T2DM group.The ISI of the NC,TlDM and T2DM groups were 12.83±1.09,9.95±0.50,3.80±0.20,respectively.There was significant difference among the three groups(P＜0.05).Conclusion The ISI in T1DM Was significantly lower than that in NC group,but higher than that in T2DM.

Association between serum level of interleukin-18 and insulin resistance in women with polycystic ovary syndrome / 中华内分泌代谢杂志

Objective To evaluate the relationship between interleukin-18(IL-18) and insulin resistance, measured by euglycemic hyperinsulinemic clamp, in women with polycystic ovary syndrome (PCOS). Methods Forty-two young women with PCOS and 38 age-and body mass index (BMI)- matched control women were recruited in this study. A complete hormonal assay was performed and serum IL-18 level was determined in each subject. And euglycemic hyperinsulinemic clamp test was completed in 41 of the above subjects. Results Serum IL-18 levels were increased in the PCOS women, as compared with the control (P=0.033). When all subjects were divided into lean and obese groups, the IL-18 levels were slightly increased in the obese subjects (P=0.902). IL-18 levels were negatively correlated with all the clamp parameters [mean glucose infusion rate (M), M-to-insulin ratio (M/I) and glucose metabolic clearance rate (MCRg), r =-0.419,-0.396,and-0.405,P=0.006,0.010 and 0.009 respectively], but were positively associated with HOMA-β index(r=0.334, P=O.035). Conclusion Serum IL-18 level was significantly increased in PCOS women and was strongly associated with the parameters obtained from the euglycemic hyperinsulinemic clamp, indicating that IL-18 may be an important mediator between inflammation and insulin resistance.

Effect of Rhizoma Coptidis apozem on expression of AMP-activated protein kinase in skeletal muscle of metabolic syndrome rats / 中华中医药杂志

Objective:To study the effect of Rhizoma Coptidis apozem on expression of AMP-activated protein kinase(AMPK) in skeletal muscle of metabolic syndrome rats. Methods:The models were established by administering high fat diet. Rats were randomly divided into five group: normal control group, metabriolic syndome group, Rhizoma Coptidis apozem group, Berberine group, Metformin group. To estimate insulin resistance by euglycemic hyperinsulinemic glucose clamp(GC) tecchnique. To estimate expression of AMPK by using Western blot. Results: Compared with metabolic syndrome group, Rhizoma Coptidis apozem group had higher M-value, lower wet weight of innards fat, and higher protein level of p-AMPK-?. Conclusion: Rhizoma Coptidis apozem can improve insulin resistance, decrease innards fat, and regulate up expression of AMPK.

A High Carbohydrate Diet Induces Insulin Resistance Through Decreased Glucose Utilization in Ovariectomized Rats

BACKGROUND: Recent research has reported that high sugar diets increase insulin resistance, without abdominal obesity, in male, but not female Wister rats. Whether a high sucrose (SU) diet increased insulin resistance in ovariectomized (OVX) rats was determined. METHODS: Female Sprague Dawley rats, weighing 273 +/- 20 g, had either an ovariectomy or a sham operation (sham). OVX and sham rats were divided into two groups: one group had a 68 En% SU diet and the other a 68 En% starch (ST) diet for 8 weeks. RESULTS: The body weight was higher in the OVX than the sham rats, regardless of dietary carbohydrate subtype. The fasting serum glucose levels did not differ according to diet and ovariectomy. However, the fasting serum insulin levels were higher in the OVX than the sham rats, and in the OVX rats, a high SU diet increased the serum insulin levels more than a high ST diet. The whole body glucose disposal rates, which referred to the state of insulin sensitivity, were lower in the OVX rats fed both the high SU and ST diets, compared to sham rats. Glycogen deposits in the soleus and quadriceps muscles were lower in the OVX rats fed high SU and ST diets than in sham rats. The glucose transporter 4 content and fraction velocity of glycogen synthase in muscles showed similar glucose disposal rates. However, the triacylglycerol content in the muscles were higher in the OVX rats with a high SU diet than those with a high ST diet. CONCLUSION: These results suggested that an OVX increased the weight gain due to higher food intakes, regardless of dietary carbohydrate subtypes. OVX-induced obesity may be involved in the induction of insulin resistance from an increased triacylglycerol content, decreased glucose uptake and glycogen synthesis in skeletal muscles, regardless of dietary carbohydrate subtypes.

The Effect of Cilostazol on Glucose Tolerance and Insulin Resistance in a Rat Model of Non-insulin Dependent Diabetes Mellitus

BACKGROUND: It has been reported that many peripheral vasodilating drugs might improve insulin resistance. Cilostazol, a antithrombotic agent, increases peripheral blood flow in non-insulin dependent diabetic patients. The effect of cilostazol treatment on insulin resistance in streptozotocin (STZ)-induced non-insulin dependent diabetic Wistar rats was examined. METHODS: About a half of two-day old neonate siblings were injected intraperitoneally with STZ and maintained for six months, at which time they were compared with age-matched control rats for intraperitoneal glucose tolerance test (IPGTT) and for glucose infusion rate (GINF) in a euglycemic hyperinsulinemic glucose-clamp study. After that, these studies were also performed after feeding rat chow containing cilostazol (100 mg/kg/day) to rats with STZ-induced non-insulin dependent diabetes mellitus for four-weeks and compared with those of age-matched control rats. RESULTS: In the intraperitoneal glucose tolerance test studies, plasma glucose levels of STZ-induced non-insulin dependent diabetic rats were significantly higher and plasma insulin levels significantly lower than those of age-matched control rats in the age of six months. Glucose infusion rate was lower in STZ-induced non-insulin dependent diabetic rats than those of age-matched control rats. However, after a four-week cilostazol treatment, glucose infusion rate of STZ-induced non-insulin dependent diabetic rats was not significantly different from that of control rats. CONCLUSION: These findings suggested that cilostazol may improve insulin resistance in STZ-induced non-insulin dependent diabetic rats.

The effect of w-6 polyunsaturated fat and vitamin E intakes on insulin resistance in 90% pancreatectomized rats / 대한내과학회지

High intake of omega-6 polyunsaturated fat (PUFA) can increase oxidative stress, which may in turn increase insulin resistance and be the cause of metabolic syndrome X (diabetes mellitus). One of the ways to reduce oxidative stress is through the consumption of antioxidants, such as vitamin E. However, it is controversial whether the consumption of vitamin E alleviates insulin resistance. The purpose of this study was to determine whether the excessive intake of omega-6 polyunsaturated fat and vitamin E influences the whole body glucose disposal rate (GDR), glycogen deposits in the liver and muscles, and the triglyceride content of muscles in 90% pancreatectomized rats. METHODS: Mildly diabetic rats were produced by removing 90% of the pancreas from Sprague Dawley rats aged 8 weeks. One week after surgery, the blood glucose levels of rats were more than 9.4 mmol/L, according to which the rats are considered to be diabetic. Two factors were examined in the 90% pancreatectomized rats: polyunsaturated fat levels with 40% and 10% of total energy intakes, and vitamin E contents with 300 IU and 30 IU per kg of diet mixture. Four different diets were given for 8 weeks. After 7 weeks of diet consumption indwelling catheters were inserted in the carotid artery and jugular vein of all rats so that the GDR could be measured while the rats were awake and in a relaxed state. RESULTS: Daily calorie and PUFA fat intake levels were higher in the high PUFA groups of diabetic rats. Daily vitamin E intake of the high vitamin E groups was ten times higher than that of the low vitamin E groups (p<0.0001). The GDR was lower in high PUFA groups, and the high intake of vitamin E tended to decrease the GDR in diabetic rats. The GDR of DHPHE was significantly lower than that of DLPLE (p<0.05). Sham operated rats (the control group) had a higher GDR by 44% than diabetic rats. Vitamin E deposits in the liver in DHPHE were higher in DLPLE (p<0.05). Glycogen deposits in the liver of diabetic rats were significantly higher in DLPLE than DHPLE. Muscle glycogen content showed a similar tendency to liver glycogen content in different diet groups of diabetic rats. Triglyceride deposits in muscles did not differ according to dietary fat and vitamin E contents in diabetic rats. CONCLUSIONS: High intake of omega-6 PUFA increased insulin resistance, and high vitamin E intake did not alleviate insulin resistance. Thus, increased oxidative stress may be an independent factor for increased insulin resistance in high intake of omega-6 PUFA. It is necessary to consume a minimum amount of omega-6 PUFA as well as the Recommended Daily Allowance of vitamin E.

The Effect of Surgical Stress on Insulin Resistance in Rats / 대한내분비학회지

BACKGROUND: It has been reported that surgical stress increased insulin resistance in human. However, there was no research about insulin resistance induced by surgical sttess in Korea. Catheters needed to be inserted in carotid artery and jugular vein of male Sprague Dawley rats to perform euglycemic hyperinsulinemic clamp procedures. The insertion of catheters in rats is a major surgery, which may increase insulin resistance. The purpose of the study is to determine whether surgical stress influence the insulin resistance. METHODS: The euglycemic hyperinsulinemie clamp procedures were performed 5 hours and 7 days after insertion of catheter in carotid artery and jugular vein. A continuous intravenous infusion of insulin was started at a rate of 12 mU/kg/minute and continued for 2 hours. Twenty-five percent glucose solution was infused through the venous line at a various rate to maintain blood glucose at 5.0-5.6 mmol/L and calculated the glucose disposal rate. Blood was collected from arterious line every 5 minutes and measured serum glucose and insulin levels. RESULTS: Prior to the clamp procedures, serum glucose levels of 5 hours and 7 days after catheter insertion were 29.8 +/- 9.8 and 7.8 +/- 0.9mmol/L, respectively. However, basal serum insulin levels were not different between 5 hours and 7 days after surgery. The glucose disposal rates were remarkably higher in rats who recovered from the surgery (22.0 +/- 7.8 mg/kg/minute) than those who did not (2.2 +/- 2.7 mg/kg/minute). Thus, surgical stress increased insulin resistance in male Sprague Dawley rats. CONCLUSION: Since surgery of catheter insertion increased insulin resistance about 10 times, euglycemic hyperinsulinemic clamp study should be performed in rats who completely recovered from the surgical stress.

Impaired Glucose Tolerance Associated with Klinefalter Syndrome / 대한내분비학회지

Klinefelter syndrome is one of the most common forms of primary hypogonadism and infertility in males. It is a clinical syndrome consisting of gynecomastia, azoospermia, and increased urinary excretion of follicle-stimulating hormone. Fequency of diabetes mellitus, emphysema, asthma, breast cancer increase in Klinefelter syndrome. We report a 16-year-old male patient with impaired glucose tolerance in association with Klinefelter syndrome, which was confirmed by chromosome analysis. The mechanism of impaired glucose tolerance in this patient was peripheral insulin resistance which clarified by euglycemic hyperinsulinemic clamp test.

On the endothelium-dependent vasodilation function in insulin-resistant rats / 中华内分泌代谢杂志

Objective To observe the change of endothelium-dependent vasodilatation function and to explore its mechanism in insulin-resistant (IR) rats induced by high fat feed. Methods (1) IR rat model was established by high fat feed for 4 weeks and IR was evaluated by glucose infusion rate (GIR) of euglycemic hyperinsulinemic clamp technique. (2) Acetylcholine (Ach)-dependent vasodilation response and nitric oxide synthase (NOS)-nitric oxide (NO)-cGMP function status were observed in isolated aorta of rats. Results (1) GIR was obviously lower in high fat feed group than that in routine feed group (P

The insulin resistance after traumatic brain injury in rats / 重庆医科大学学报

Objective:To study the insulin resistance after traumatic brain injury in rats.Methods:Based upon the Feeney's model,the blood glucose and insulin concentration of each animal group were measured 1/2 hour before injury and 6,12,24,48,72,120 hours after injury;the three indices BG_(60-120),GIR_(60-120),ISI reflecting the insulin sensitivity were measured 24 hours after severe traumatic brain injury by euglycemic-hyperinsulinemic clamp technique.Results:Both the blood glucose and insulin concentration increased markedly in medium and severely injured group after injury.BG_(60-120) increased markedly and GIR_(60-120),ISI decreased significantly 24 hours after severe trauma in injured animal compared with sham group.Conclusion:Both the blood glucose and insulin concentration increase markedly in severe injured group after injury.The fact that higher-level insulin cannot reduce the increased blood glucose is due to acute insulin resistance developing after traumatic brain injury.