scholarly journals Improved functional vasodilation in obese Zucker rats following exercise training

2011 ◽  
Vol 301 (3) ◽  
pp. H1090-H1096 ◽  
Author(s):  
Mohamad Sebai ◽  
Silu Lu ◽  
Lusha Xiang ◽  
Robert L. Hester
Keyword(s):  
Insulin Resistance ◽  
Exercise Training ◽  
Glucose Tolerance ◽  
Tolerance Test ◽  
Zucker Rats ◽  
Oral Glucose ◽  
Global Effect ◽  
Thromboxane Receptor ◽  
Improve Insulin Resistance ◽  
Obese Zucker Rats

Obese individuals exhibit impaired functional vasodilation and exercise performance. We have demonstrated in obese Zucker rats (OZ), a model of morbid obesity, that insulin resistance impairs functional vasodilation via an increased thromboxane receptor (TP)-mediated vasoconstriction. Chronic treadmill exercise training improves functional vasodilation in the spinotrapezius muscle of the OZ, but the mechanisms responsible for the improvement in functional vasodilation are not clear. Based on evidence that exercise training improves insulin resistance, we hypothesized that, in the OZ, exercise training increases functional vasodilation and exercise capability due to decreases TP-mediated vasoconstriction associated with improved insulin sensitivity. Six-week-old lean Zucker rats (LZ) and OZ were exercised on a treadmill (24 m/min, 30 min/day, 5 days/wk) for 6 wk. An oral glucose tolerance test was performed at the end of the training period. We measured functional vasodilation in both exercise trained (spinotrapezius) and nonexercise trained (cremaster) muscles to determine whether the improved functional vasodilation following exercise training in OZ is due to a systemic improved insulin resistance. Compared with LZ, the sedentary OZ exhibited impairments in glucose tolerance and functional vasodilation in both muscles. The TP antagonist SQ-29548 improved the vasodilator responses in the sedentary OZ with no effect in the LZ. Exercising training of the LZ increased the functional vasodilation in spinotrapezius muscle, with no effect in the cremaster muscle. Exercising training of the OZ improved glucose tolerance, along with increased functional vasodilation, in both the spinotrapezius and cremaster muscles. SQ-29548 treatment had no effect on the vasodilator responses in either cremaster or spinotrapezius muscles of the exercise-trained OZ. These results suggest that, in the OZ, there is a global effect of exercising training to improve insulin resistance and increase functional vasodilation via a decreased TP-mediated vasoconstriction.

scholarly journals Plasma calcitonin gene-related peptide is increased prior to obesity, and sensory nerve desensitization by capsaicin improves oral glucose tolerance in obese Zucker rats

2005 ◽  
Vol 153 (6) ◽  
pp. 963-969 ◽  
Author(s):  
Dorte X Gram ◽  
Anker J Hansen ◽  
Michael Wilken ◽  
Torben Elm ◽  
Ove Svendsen ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Glucose Tolerance ◽  
Sensory Nerve ◽  
Zucker Rats ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Nerve Activity ◽  
Calcitonin Gene ◽  
Obese Rats ◽  
Obese Zucker Rats

Objective: It has earlier been demonstrated that capsaicin-induced desensitization improves insulin sensitivity in normal rats. However, whether increased capsaicin-sensitive nerve activity precedes the onset of insulin resistance in diet-induced obesity – and therefore might be involved in the pathophysiology – is not known. Further, it is of relevance to investigate whether capsaicin desensitization improves glycaemic control even in obese individuals and we therefore chose the obese Zucker rats to test this. Design and methods: Plasma levels of calcitonin gene-related peptide (CGRP; a marker of sensory nerve activity) was assessed in 8-week-old Zucker rats. To investigate whether capsaicin desensitization (100 mg/kg at 9 weeks of age) would also ameliorate glycaemia in this non-diabetic model, we assessed oral glucose tolerance at 7 weeks after capsaicin. Results: It was found that plasma CGRP levels were elevated in obese Zucker rats prior to the onset of obesity (16.1±3.4 pmol/l in pre-obese Zucker rats vs 6.9±1.1 pmol/l in lean littermates; P = 0.015) despite similar body weights. Furthermore, capsaicin desensitization reduced both fasting blood glucose (4.3±0.2 mmol/l vs 5.1±0.2 mmol/l in controls; P = 0.050) as well as the mean blood glucose level during an oral glucose tolerance test (OGTT) (6.8±0.3 mmol/l vs 8.6±0.5 mmol/l in control obese rats; P = 0.024) whereas the plasma insulin levels during the OGTT were unchanged. However this did not lead to an improvement in insulin resistance or to a reduction of tissue triglyceride accumulation in muscle or liver. Conclusion: We concluded that capsaicin-induced sensory nerve desensitization improves glucose tolerance in Zucker rats. Since, in this study, plasma CGRP levels, a marker of sensory nerve activity, were increased in the pre-obese rats, our data support the hypothesis that increased activity of sensory nerves precedes the development of obesity and insulin resistance in Zucker rats.

Tesaglitazar, a dual PPARα/γ agonist, ameliorates glucose and lipid intolerance in obese Zucker rats

2005 ◽  
Vol 289 (4) ◽  
pp. R938-R946 ◽  
Author(s):  
Nicholas D. Oakes ◽  
Pia Thalén ◽  
Therese Hultstrand ◽  
Severina Jacinto ◽  
Germán Camejo ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Metabolic Syndrome ◽  
Glucose Tolerance ◽  
Zucker Rats ◽  
Oral Glucose ◽  
Therapeutic Effects ◽  
The Metabolic Syndrome ◽  
Increased Risk ◽  
Mass Load ◽  
Obese Zucker Rats

Insulin resistance, impaired glucose tolerance, high circulating levels of free fatty acids (FFA), and postprandial hyperlipidemia are associated with the metabolic syndrome, which has been linked to increased risk of cardiovascular disease. We studied the metabolic responses to an oral glucose/triglyceride (TG) (1.7/2.0 g/kg lean body mass) load in three groups of conscious 7-h fasted Zucker rats: lean healthy controls, obese insulin-resistant/dyslipidemic controls, and obese rats treated with the dual peroxisome proliferator-activated receptor α/γ agonist, tesaglitazar, 3 μmol·kg−1·day−1 for 4 wk. Untreated obese Zucker rats displayed marked insulin resistance, as well as glucose and lipid intolerance in response to the glucose/TG load. The 2-h postload area under the curve values were greater for glucose (+19%), insulin (+849%), FFA (+53%), and TG (+413%) compared with untreated lean controls. Treatment with tesaglitazar lowered fasting plasma glucose, improved glucose tolerance, substantially reduced fasting and postload insulin levels, and markedly lowered fasting TG and improved lipid tolerance. Fasting FFA were not affected, but postprandial FFA suppression was restored to levels seen in lean controls. Mechanisms of tesaglitazar-induced lowering of plasma TG were studied separately using the Triton WR1339 method. In anesthetized, 5-h fasted, obese Zucker rats, tesaglitazar reduced hepatic TG secretion by 47%, increased plasma TG clearance by 490%, and reduced very low-density lipoprotein (VLDL) apolipoprotein CIII content by 86%, compared with obese controls. In conclusion, the glucose/lipid tolerance test in obese Zucker rats appears to be a useful model of the metabolic syndrome that can be used to evaluate therapeutic effects on impaired postprandial glucose and lipid metabolism. The present work demonstrates that tesaglitazar ameliorates these abnormalities and enhances insulin sensitivity in this animal model.

scholarly journals QOL-43. ENDOCRINE AND METABOLIC CHANGES IN CHILDREN TREATED FOR MEDULLOBLASTOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii439-iii439
Author(s):  
Alexey Kalinin ◽  
Natalia Strebkova ◽  
Olga Zheludkova
Keyword(s):  
Insulin Resistance ◽  
Body Composition ◽  
Glucose Tolerance ◽  
Oral Glucose Tolerance Test ◽  
Impaired Glucose Tolerance ◽  
Glucose Tolerance Test ◽  
Tolerance Test ◽  
Hormone Deficiency ◽  
Oral Glucose ◽  
Oral Glucose Tolerance

Abstract We examined 63 patients (40 males/23 females) after complex treatment of medulloblastoma. Patients had a median age (range) of 11.3 (5.5 ÷ 17.9) years. The median time after the end of treatment was 3.7 (1.5 ÷ 11.6) years. Endocrine disorders were detected with the following frequency: growth hormone deficiency - 98.41% (62 of 63 patients), thyroid hormone deficiency – 69.8% (44/63), adrenal hormone deficiency - 17.4% (11/63). Three cases (4.7%) of premature sexual development were also detected. Lipids levels, beta-cell function and insulin resistance (IR) during 2-h oral glucose tolerance test were evaluated. A mono frequent bioelectrical impedanciometer was used to measure body composition. Overweight (SDS BMI> 1) was observed only in 16 patients (3 girls and 13 boys), obesity (SDS BMI> 2) in 1 boy. Dyslipidemia was found in 34 patients (54%). All patients underwent oral glucose tolerance test. Insulin resistance (ISI Matsuda <2.5 and/or HOMA-IR> 3.2) was detected in 7 patients (11/1%), impaired glucose tolerance (120 min glucose ≥7.8 mmol / l) was observed in 2 patients with IR and in 2 patients without IR. At the same time, IR and impaired glucose tolerance were encountered in only 5 children with overweight and no one with obesity. All patients with impaired glucose tolerance had normal values of fasting glucose (4.3 ÷ 5.04 mmol / l) and HbA1c (4.8 ÷ 5.8%). A bioelectrical impedanciometer was used to measure body composition in 49 cases, the percentage of adipose tissue was increased in 14 patients (28%) with normal BMI.

Abstract P177: Effects of Gender, Race, and Glucose Tolerance on Lipoprotein Insulin Resistance Index Responses to Exercise Training

Circulation ◽  
2020 ◽  
Vol 141 (Suppl_1) ◽  
Author(s):  
Leanna M Ross ◽  
Cris A Slentz ◽  
Irina Shalaurova ◽  
Margery A Connelly ◽  
James D Otvos ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Exercise Training ◽  
Glucose Tolerance ◽  
Resistance Index ◽  
Analysis Of Covariance ◽  
Oral Glucose ◽  
Exercise Interventions ◽  
Insulin Resistance Index ◽  
Lower Baseline ◽  
Baseline Values

Introduction: Lipoprotein Insulin Resistance Index (LP-IR) is a novel spectroscopic multimarker linked to future diabetes risk. We recently assessed changes in LP-IR across the three STRRIDE trials, where on average, STRRIDE exercise interventions improved LP-IR. In the present study, we sought to determine if there were effects of gender, race, and glucose tolerance on LP-IR responses across the STRRIDE trials. Methods: A total of 461 adults with dyslipidemia (STRRIDE I and STRRIDE AT/RT) or prediabetes (STRRIDE-PD) were randomized to one of 7 exercise interventions, ranging from doses of 8-22 kcal/kg/week (KKW); intensities of 50-75% VO 2peak ; and durations of 6-9 months. Six groups included aerobic exercise, two groups included resistance training, and one group included dietary intervention (weight loss goal of 7%). Fasting blood samples were obtained at both baseline and 16-24 h after the final exercise bout. In STRRIDE-PD only (n=165), subjects completed oral glucose tolerance tests and were categorized into normal (NGT) and impaired glucose tolerance (IGT) groups at baseline. NMR spectroscopy was performed at LabCorp to determine LP-IR score (comprised of six lipoprotein subclass and size parameters). LP-IR score ranges from 0 (most insulin sensitive) to 100 (most insulin resistant). Irrespective of intervention group, we assessed change in LP-IR in three stratified analyses: by gender, race, and baseline glucose tolerance category. Paired t-tests determined whether the post- minus pre- intervention change scores within each group were significant (p<0.05). Analysis of covariance accounting for baseline values determined difference among groups. Results: At baseline, women had lower LP-IR scores compared to men (47.8 ± 22.3 vs 62.6 ± 21.5; p<0.0001). Both women and men significantly improved LP-IR following exercise training by -4.3 ± 15.0 and -8.0 ± 15.6 points, respectively. There were also significant baseline differences when stratified by race. Black subjects had lower baseline LP-IR scores compared to White subjects (43.2 ± 20.7 vs 56.3 ± 23.0; p<0.0001). After exercise training, Black subjects significantly improved their LP-IR score by -4.0 ± 14.6 points; White subjects significantly improved their LP-IR score by -6.2 ± 15.5 points. As expected, those with NGT had lower baseline LP-IR scores compared to those with IGT in STRRIDE-PD (49.0 ± 20.0 vs 64.4 ± 19.9; p<0.0001). Both NGT and IGT groups significantly improved LP-IR by -4.3 ± 14.6 and -7.6 ± 12.9 points, respectively. In all three stratified analyses, change in LP-IR was not significantly different among groups after controlling for baseline values. Conclusion: There were significant baseline differences in LP-IR among gender, racial, and glucose tolerance groups. However, after adjusting for these baseline differences, there were similar beneficial responses to exercise in this marker of insulin resistance.

scholarly journals Compound Danshen Dripping Pills Prevented Leptin Deficiency-Induced Hepatic ER Stress, Stimulated Autophagy, and Improved Insulin Resistance of ob/ob Mice

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Yanan Shi ◽  
Dan Liu ◽  
Jihong Yuan ◽  
Lihui Yan ◽  
Zhenfeng Zhan ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Glucose Tolerance ◽  
Er Stress ◽  
Heart Diseases ◽  
Fasting Blood Glucose ◽  
Underlying Mechanism ◽  
Hepatic Function ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Signal Sensitivity

Compound Danshen dripping pills (CDDP) is widely used for the treatment of coronary arteriosclerosis and ischemic heart diseases for decades of years. In our study, we interestingly discovered the effects and mechanism of CDDP on insulin resistance that increase the risk factor of cardiovascular diseases. Effects of CDDP on fasting blood glucose, the insulin tolerance test (ITT), the oral glucose tolerance test (OGTT), hepatic function, and underlying mechanism were analyzed in ob/ob mice. CDDP was found improving the impaired insulin signal sensitivity of ob/ob mice by ameliorating insulin and glucose tolerance, improving hepatic phosphorylation of the insulin receptor substrate-1 on Ser 307 (pIRS1) of ob/ob mice, and restoring hepatic function by decreasing serum ALT and AST, which increased in ob/ob mice serum. Decreasing hepatic phosphorylation of pancreatic ER kinase (PERK) and inositol-requiring enzyme-1 (IRE1) regulating hepatic ER stress in the liver of ob/ob mice were increased by CDDP. Furthermore, CDDP was also found stimulating ob/ob mice hepatic autophagy by increasing the expression of Beclin1 and LC3B, while decreasing P62 expression. Our study discovered an important role of CDDP on improving ob/ob mice insulin resistance and liver function probably through relieving hepatic ER stress and stimulating hepatic autophagy, which would broaden the application value and provide more benefits for treating cardiovascular patients. This trial is registered with NCT01659580.

Insulin resistance caused by amylin in conscious rats is independent of induced hypocalcemia and fades during long-term exposure

1993 ◽  
Vol 129 (4) ◽  
pp. 360-365 ◽  
Author(s):  
Clemens Fürnsinn ◽  
Peter Nowotny ◽  
Michael Roden ◽  
Madeleine Rohac ◽  
Thomas Pieber ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Glucose Intolerance ◽  
Tolerance Test ◽  
Zucker Rats ◽  
Control Group ◽  
Short Term ◽  
Euglycemic Hyperinsulinemic Clamp

To compare the effect of short- vs long-term amylin infusion on insulin sensitivity, glucose tolerance and serum calcemia, euglycemic-hyperinsulinemic clamp (26 pmol·kg−1·min−1) and glucose tolerance tests (2.4 mmol/kg over 30 min) were performed in lean Zucker rats. Three infusion protocols were employed: control group: 24 h of iv saline; short-term amylin exposure: 22 h of iv saline followed by 2 h of iv amylin (20 μg/h); long-term amylin exposure: 24 h of iv amylin (20 μg/h). Insulin resistance was induced by short-term amylin infusion during euglycemic clamping, as shown by a 41% decrease in space-corrected glucose infusion rates (μmol·kg−1·min−1; control group, 106.0±15.0; short-term iv amylin, 62.7±15.0; p<0.00 5). After long-term amylin exposure, insulin sensitivity was identical to control values (109.9±6.7). This fading action of amylin was confirmed by data from the glucose tolerance test, demonstrating glucose intolerance after short- but not after long-term amylin exposure. Serum calcium concentration decreased during short-term (2 h) amylin infusion (from 2.52±0.15 to 2.09±0.12 mmol/l; p<0.01) and hypocalcemia of a similar extent also was present after 22 h and 24 h of amylin exposure (2.10±0.09 and 2.04±0.14 mmol/l, respectively). The data demonstrate that short-term amylin infusion induces insulin resistance and glucose intolerance, both of which vanish during long-term (>22 h) amylin exposure, being apparently independent of induced hypocalcemia.

scholarly journals The Role of Insulin-Like Growth Factor (IGF) Binding Protein-2 in the Insulin-Mediated Decrease in IGF-I Bioactivity

Endocrinology ◽  
2009 ◽  
Vol 150 (11) ◽  
pp. 5192-5192
Author(s):  
Ayman M. Arafat ◽  
Martin O. Weickert ◽  
Jan Frystyk ◽  
Joachim Spranger ◽  
Christof Schöfl ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Metabolic Syndrome ◽  
Glucose Tolerance ◽  
Glucose Tolerance Test ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Igf System ◽  
Igf I ◽  
Igf Binding

ABSTRACT Context: Insulin interacts with the GH-IGF system by a reciprocal regulation of IGF-binding proteins (IGFBP) and GH, which in turn regulate insulin sensitivity via bioactive IGF-I. This network is linked to metabolic syndrome and cardiovascular diseases. Objective: We evaluated the effect of glucose and insulin on IGFBP-1-4, particularly IGFBP-2, in the regulation of bioactive IGF-I and its relation to insulin resistance. Setting: The study was conducted at an endocrinology center. Research Design and Methods: Twenty-four healthy subjects (12 men; aged 21–72 yr; body mass index 25.9 ± 0.9 kg/m2) and 19 subjects with impaired glucose tolerance (IGT; eight men; aged 26–71 yr; body mass index 28.9 ± 1.2 kg/m2 ) were prospectively studied using oral glucose tolerance test and hyperinsulinemic euglycemic clamp. Results: During the clamp, insulin decreased IGF-I bioactivity in both IGT subjects and controls (−16.2 ± 2.8 and −13.9 ± 3.3%, respectively; P &lt; 0.01). In addition, insulin increased IGFBP-2 and GH and decreased IGFBP-1 and -4 but did not alter total IGF-I, IGF-II, or IGFBP-3 levels. During the oral glucose tolerance test, GH and IGFBP-1 were markedly suppressed. Subjects with IGT showed more pronounced insulin resistance and lower GH, IGFBP-1, and IGFBP-2 levels (P &lt; 0.05). In multiple regression analysis, IGFBP-2 was an independent predictor of insulin sensitivity (β = 0.36, P &lt; 0.05) and IGF-I bioactivity (β = −0.5, P &lt; 0.05). Conclusions: Our data indicate that insulin acutely decreases IGF-I bioactivity through differential modulation of IGFBPs. Furthermore, IGFBP-2 plays a central role in the insulin-IGF system cross talk and is closely linked to insulin resistance, thereby providing a further explanation for its association with the metabolic syndrome.

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