The effect of exercise training on insulin sensitivity and fat and muscle tissue cytokine profiles of old and young Standardbred mares

2011 ◽  
Vol 31 (5-6) ◽  
pp. 237-238 ◽  
Author(s):  
N.R. Liburt ◽  
M.N. Fugaro ◽  
E.K. Wunderlich ◽  
J.L. Zambito ◽  
D.W. Horohov ◽  
...  
2012 ◽  
Vol 8 (3-4) ◽  
pp. 173-187 ◽  
Author(s):  
N.R. Liburt ◽  
M.N. Fugaro ◽  
K. Malinowski ◽  
E.K. Wunderlich ◽  
J.L. Zambito ◽  
...  

This study tested the hypothesis that old and young mares exhibit different endocrine responses to a frequently sampled intravenous glucose tolerance test (FSIGT) and different cytokine profiles in blood, adipose and muscle tissues. It was also hypothesised that exercise training alters endocrine and tissue cytokine profiles. Pilot data from 15 mixed background horses indicated tissue differences in cytokine profiles. For the main study, six old (22.0±0.7 years) and six young (7.3±0.6 years; mean±SE) unfit Standardbred mares were tested pre- and post-training. Exercise training occurred three days/week for 15 weeks at ~60% maximum heart rate. Plasma insulin and glucose concentrations were measured via radioimmunoassay and enzyme-electrode interface, respectively. Samples of blood, middle gluteal muscle (RM), and subcutaneous adipose tissue from the neck (NF) were collected pre- and post-training for mRNA quantification. Minimal model analysis of FSIGT, repeated measures ANOVA and Pearson Product Moment were used to analyse data. The null hypothesis was rejected when P≤l0.10. Post-training, old and young mares improved insulin sensitivity (SI) (P=0.08, P=0.01, respectively) and disposition index (P=0.04, P<0.001, respectively), but acute insulin response to glucose increased in young mares only (P=0.02). Old mares exhibited lower (P=0.06) average relative quantity (RQ) of tumour necrosis factor-alpha in NF compared to RM. Old mares showed greater RQ of interleukin-6 (IL-6) in NF compared to young (P=0.08). A negative correlation was observed between SI and IL-6 in NF post-training (P=0.07, R=-0.54), and a positive correlation occurred between SI and monocyte chemotactic protein-1 in NF post-training (P=0.08, R=0.53). Exercise training improved pancreatic beta cell function and insulin sensitivity in old and young horses. Cytokines associated with glucose metabolism may have varied roles in different tissues.


1986 ◽  
Vol 250 (5) ◽  
pp. E570-E575
Author(s):  
G. K. Grimditch ◽  
R. J. Barnard ◽  
S. A. Kaplan ◽  
E. Sternlicht

We examined the hypothesis that the exercise training-induced increase in skeletal muscle insulin sensitivity is mediated by adaptations in insulin binding to sarcolemmal (SL) insulin receptors. Insulin binding studies were performed on rat skeletal muscle SL isolated from control and trained rats. No significant differences were noted between groups in body weight or fat. An intravenous glucose tolerance test showed an increase in whole-body insulin sensitivity with training, and specific D-glucose transport studies on isolated SL vesicles indicated that this was due in part to adaptations in skeletal muscle. Enzyme marker analyses revealed no differences in yield, purity, or contamination of SL membranes between the two groups. Scatchard analyses indicated no significant differences in the number of insulin binding sites per milligram SL protein on the high-affinity (15.0 +/- 4.1 vs. 18.1 +/- 6.4 X 10(9)) or on the low-affinity portions (925 +/- 80 vs. 884 +/- 106 X 10(9)) of the curves. The association constants of the high-affinity (0.764 +/- 0.154 vs. 0.685 +/- 0.264 X 10(9) M-1) and of the low affinity sites (0.0096 +/- 0.0012 vs. 0.0102 +/- 0.0012 X 10(9) M-1) also were similar. These results do not support the hypothesis that the increased sensitivity to insulin after exercise training is due to changes in SL insulin receptor binding.


Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 637
Author(s):  
Shengyan Sun ◽  
Zhaowei Kong ◽  
Qingde Shi ◽  
Haifeng Zhang ◽  
On-Kei Lei ◽  
...  

Objective: The purpose of this study was to evaluate the effects of a 4-week low-carbohydrate diet (LC) with or without exercise training on cardiometabolic health-related profiles in overweight/obese women. Methods: Fifty overweight/obese Chinese women (age: 22.2 ± 3.3 years, body mass index (BMI): 25.1 ± 3.1 kg·m−2) were randomized to either a LC control group (LC-CON, n = 16), a LC and high-intensity interval training group (LC-HIIT, n = 17), or a LC and moderate-intensity continuous training group (LC-MICT, n = 17). All groups consumed LC for 4 weeks, while the LC-HIIT and LC-MICT groups followed an additional five sessions of HIIT (10 × 6 s cycling sprints and 9 s rest intervals, 2.5 min in total) or MICT (cycling continuously at 50–60% of peak oxygen uptake (VO2peak) for 30 min) weekly. Blood pressure, fasting glucose, insulin sensitivity, and several metabolic or appetite regulating hormones were measured before and after intervention. Results: Significant reductions in body weight (− ~2.5 kg, p < 0.001, η2 = 0.772) and BMI (− ~1 unit, p < 0.001, η2 = 0.782) were found in all groups. Systolic blood pressure was reduced by 5–6 mmHg (p < 0.001, η2 = 0.370); fasting insulin, leptin, and ghrelin levels were also significantly decreased (p < 0.05), while insulin sensitivity was improved. However, there were no significant changes in fasting glucose, glucagon, and gastric inhibitory peptide levels. Furthermore, no group differences were found among the three groups, suggesting that extra training (i.e., LC-HIIT and LC-MICT) failed to trigger additional effects on these cardiometabolic profiles. Conclusions: The short-term carbohydrate restriction diet caused significant weight loss and improved blood pressure and insulin sensitivity in the overweight/obese women, although the combination with exercise training had no additional benefits on the examined cardiometabolic profiles. Moreover, the long-term safety and effectiveness of LC needs further study.


1996 ◽  
Vol 80 (6) ◽  
pp. 1963-1967 ◽  
Author(s):  
N. Nakai ◽  
Y. Shimomura ◽  
N. Ohsaki ◽  
J. Sato ◽  
Y. Oshida ◽  
...  

We examined the effects of exercise training initiated before maturation or after maturation on insulin sensitivity and glucose transporter GLUT-4 content in membrane fractions of skeletal muscle. Female Wistar rats (4 wk of age) were divided into sedentary and exercise-trained groups. At 12 wk of age, a subset of the trained animals (Tr) was killed along with a subset of sedentary controls (Sed). One-half of the remaining sedentary animals remained sedentary (Sed-Sed) while the other half began exercise training (Sed-Tr). The remaining rats in the original trained group continued to train (Tr-Tr). Euglycemic clamp (insulin infusion rate at 6 mU.kg body wt-1. min-1) was performed at 4, 12, and 27 wk. After euglycemic clamp in all animals except the 4-wk-old, hindlimb (gastrocnemius and part of quadriceps) muscles were removed for preparation of membrane fractions. In sedentary rats, glucose infusion rate (GIR) during euglycemic clamp was decreased from 15.9 mg.kg-1.min-1 at 4 wk of age to 9.8 mg.kg-1.min-1 at 12 wk of age and 9.1 mg.kg-1.min-1 at 27 wk of age. In exercise-trained rats, the GIR was not significantly decreased by maturation (at 12 wk) and further aging (at 27 wk). Initiation of exercise after maturation restored the GIR at 27 wk of age to the same levels as these for the corresponding exercise-trained rats. GLUT-4 content in plasma and intracellular membrane fractions of hindlimb muscle obtained just after euglycemic clamp showed the same trend as the results of GIR. These results suggest that exercise training prevented the maturation-induced decrease in insulin sensitivity. Improvement of insulin sensitivity caused by exercise training was attributed, at least in part, to the increase in insulin-sensitive GLUT-4 on the plasma membrane in skeletal muscle.


Diabetologia ◽  
2006 ◽  
Vol 50 (2) ◽  
pp. 404-413 ◽  
Author(s):  
F. Shojaee-Moradie ◽  
K. C. R. Baynes ◽  
C. Pentecost ◽  
J. D. Bell ◽  
E. L. Thomas ◽  
...  

2014 ◽  
Vol 10 (3) ◽  
pp. 167-172 ◽  
Author(s):  
S.E. Pratt-Phillips ◽  
R.J. Geor ◽  
M. Buser ◽  
A. Zirkle ◽  
A. Moore ◽  
...  

Two experiments were designed to investigate the role of exercise on insulin sensitivity (IS) in Alaskan racing sled dogs. In both experiments, IS was quantified with an isoglycemic-hyperinsulinemic clamp (IHC), whereby IS was defined as the glucose infusion rate (GIR) divided by the mean insulin concentration during the clamp. In Experiment 1, IS was quantified in 12 racing sled dogs during three stages of exercise training: unexercised for 4 months over the summer (deconditioned), and after two and four months of exercise conditioning. At each stage IS was assessed in unexercised dogs (n=6) and 60 h following a standard exercise challenge (n=6) consisting of a 35.4 km run completed in 2.5 h. In Experiment 2, IS was assessed in deconditioned dogs (n=6) and in well-conditioned dogs that had either completed a 708 km race 5-days prior (n=3) or were unraced for the previous month (n=3). In Experiment 1, there were no significant differences (Pã0.05) in GIR or IS between the three levels of conditioning, nor were there any effects of the exercise bout 60 h prior to the IHC. In Experiment 2 there was no significant difference in IS between well-conditioned dogs and untrained dogs (Pã0.05). However, dogs that completed a 708 km race 5-days prior to the IHC had a significantly higher IS than dogs that were deconditioned and those that were conditioned but unraced. These results suggest that the workload of an exercise challenge is a factor in post-exercise changes in IS but that exercise conditioning has little impact on IS in Alaskan sled dogs.


Life Sciences ◽  
2017 ◽  
Vol 191 ◽  
pp. 17-23 ◽  
Author(s):  
Rafael Barrera Salgueiro ◽  
Frederico Gerlinger-Romero ◽  
Lucas Guimarães-Ferreira ◽  
Thais de Castro Barbosa ◽  
Maria Tereza Nunes

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