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Whole Body Insulin Sensitivity (whole + body_insulin_sensitivity)
Selected AbstractsAcute exercise reverses TRB3 expression in the skeletal muscle and ameliorates whole body insulin sensitivity in diabetic miceACTA PHYSIOLOGICA, Issue 1 2010A. Matos Abstract Aim:, TRB3 became of major interest in diabetes research when it was shown to interact with and inhibit the activity of Akt. Conversely, physical exercise has been linked to improved glucose homeostasis. Thus, the current study was designed to investigate the effects of acute exercise on TRB3 expression and whole body insulin sensitivity in obese diabetic mice. Methods:, Male leptin-deficient (ob/ob) mice swam for two 3-h-long bouts, separated by a 45-min rest period. After the second bout of exercise, food was withdrawn 6 h before antibody analysis. Eight hours after the exercise protocol, the mice were submitted to an insulin tolerance test (ITT). Gastrocnemius muscle samples were evaluated for insulin receptor (IR) and IRS-1 tyrosine phosphorylation, Akt serine phosphorylation, TRB3/Akt association and membrane GLUT4 expression. Results:, Western blot analysis showed that TRB3 expression was reduced in the gastrocnemius of leptin-deficient (ob/ob) mice submitted to exercise when compared with respective ob/ob mice at rest. In parallel, there was an increase in the insulin-signalling pathway in skeletal muscle from leptin-deficient mice after exercise. Furthermore, the GLUT4 membrane expression was increased in the muscle after the exercise protocol. Finally, a single session of exercise improved the glucose disappearance (KITT) rate in ob/ob mice. Conclusion:, Our results demonstrate that acute exercise reverses TRB3 expression and insulin signalling restoration in muscle. Thus, these results provide new insights into the mechanism by which physical activity ameliorates whole body insulin sensitivity in type 2 diabetes. [source] Rosiglitazone improves insulin sensitivity, glucose tolerance and ambulatory blood pressure in subjects with impaired glucose toleranceDIABETIC MEDICINE, Issue 5 2004S. M. A. Bennett Abstract Aims To determine the effects of rosiglitazone on insulin sensitivity, glucose tolerance and ambulatory blood pressure when administered to subjects with persistent impaired glucose tolerance (IGT). Methods Eighteen subjects with persistent IGT were randomized to receive rosiglitazone 4 mg twice daily or matching placebo for 12 weeks. Evaluation at baseline and at the end of treatment included measurement of whole body insulin sensitivity during a euglycaemic hyperinsulinaemic clamp and deriving an insulin sensitivity index. Changes in glucose and insulin concentration were determined after oral glucose tolerance test (OGTT) and mixed meal tolerance tests, and 24-h ambulatory blood pressure was monitored. Results Rosiglitazone significantly improved the insulin sensitivity index by 2.26 µg/kg per min per pmol/l relative to placebo (P = 0.0003). Four of nine subjects receiving rosiglitazone reverted to normal glucose tolerance and 5/9 remained IGT, although four of these had improved 2-h glucose values. In the placebo group, 1/9 subjects progressed to Type 2 diabetes and 8/9 remained IGT. Following OGTT and meal tolerance test, glucose and insulin area under curve were reduced over 3 and 4 h, respectively. Compared with placebo, ambulatory blood pressure decreased significantly in the rosiglitazone group by 10 mmHg systolic (P = 0.0066) and 8 mmHg diastolic (P = 0.0126). Conclusions Consistent with its effects in patients with Type 2 diabetes, rosiglitazone substantially improved whole body insulin sensitivity and the glycaemic and insulinaemic responses to an OGTT and meal tolerance test in subjects with persistent IGT. Furthermore, rosiglitazone reduced systolic and diastolic ambulatory blood pressure in these subjects. [source] Effects of short-term training on insulin sensitivity and skeletal muscle glucose metabolism in Standardbred horsesEQUINE VETERINARY JOURNAL, Issue S36 2006L. STEWART-HUNT Summary Reasons for performing study: Increased insulin sensitivity occurs after a period of exercise training, but the mechanisms underlying this training-associated increase in insulin action have not been investigated. Objective: To examine the effects of short-term endurance training (7 consecutive days) and a subsequent period of inactivity (5 days) on whole body insulin sensitivity and GLUT-4 protein and the activities of glycogen synthase (GS) and hexokinase (HK) in skeletal muscle. It was hypothesised that training would increase insulin sensitivity in association with increased GLUT-4 protein and activities of GS and HK, but that these changes would be transient, returning to baseline after 5 days of inactivity. Methods: Seven mature Standardbred horses completed training consisting of 7 consecutive days of 45 min of treadmill exercise at a speed that elicited 55% of pretraining maximal aerobic capacity (VO2peak). Insulin sensitivity was determined by rate of glucose disposal (M) during the last 60 min of a 120 min euglycaemic-hyperinsulinaemic clamp (EHC) performed before (-2 days) and at 1 and 6 days following training. VO2peak was measured before (UT) and after (TR) training and the period of inactivity (IA). Results: Training resulted in a 9% increase in mean VO2peak (P<0.05) that was maintained following inactivity (IA). Mean M values were more than 2-fold higher (P<0.05) in TR than in UT. Mean M was also higher (P<0.05) in IA when compared to UT. GLUT-4 protien abundancewas more than 10-fold higher in TR and IA (P<0.001) than in UT. Pre-EHC GS activity and GS fractional velocity were increased (P<0.05) in TR when compared to UT and IA. Pre-EHC HK activity was increased (P<0.05) in IA when compared to UT and TR. Muscle glycogen was 66% lower (P<0.05) in TR than in UT and IA. Conclusions: Short-term training resulted in increases in whole body insulin sensitivity, and GLUT-4 protein content and glycogen synthase activity in skeletal muscle. The enhancements in insulin sensitivity, GLUT-4 protein and glycogen synthase activity were still evident after 5 days of inactivity. Potential relevance: Insulin resistance in equids has been associated with obesity and predisposition to laminitis. Regular physical activity may mitigate risk of these conditions via enhancement of insulin sensitivity and/or control of bodyweight. [source] Liver dysfunction in paediatric obesity: a randomized, controlled trial of metforminACTA PAEDIATRICA, Issue 9 2007Michael Freemark Abstract Aim: In a previous study we showed that metformin reduced BMI z -scores and fasting glucose and insulin concentrations, and increased whole body insulin sensitivity in obese adolescents with fasting hyperinsulinemia and a family history of type 2 diabetes. We analyzed the data from this study to determine (a) if metformin reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations during the 6-month trial, and (b) if the response to pharmacotherapy varied along gender or ethnic lines. Methods: The 6-month trial was randomized, double blinded and placebo controlled; a total of 14 metformin-treated (500 mg bid) and 15 placebo-treated subjects completed the study. There were no dietary restrictions. Results: In obese adolescents fed ad libitum, metformin (a) prevented the rise in ALT concentrations that were observed in placebo-treated subjects at the 3 to 5 month time-points (p < 0.05); (b) reduced (p < 0.01) the percentage of all ALT values exceeding 40 U/L; and (c) caused a modest (10%) but statistically significant (p < 0.05) reduction in serum ALT in Caucasian subjects. Metformin had no effect on ALT levels or the ALT to AST ratio in the five African American adolescents enrolled in the study but reduced their fasting insulin concentrations from 26.1 to 19.5 ,U/mL (p < 0.05). Conclusions: Our findings suggest that metformin might reduce the rates or severity of liver dysfunction in selected high-risk adolescents. [source] | ||||||||||