Enlargement of glycogen store in rat liver and muscle by fructose-diet intake and exercise training

1997 ◽  
Vol 82 (3) ◽  
pp. 772-775 ◽  
Author(s):  
Taro Murakami ◽  
Yoshiharu Shimomura ◽  
Noriaki Fujitsuka ◽  
Masahiro Sokabe ◽  
Koji Okamura ◽  
...  

Murakami, Taro, Yoshiharu Shimomura, Noriaki Fujitsuka, Masahiro Sokabe, Koji Okamura, and Shuichi Sakamoto. Enlargement of glycogen store in rat liver and muscle by fructose-diet intake and exercise training. J. Appl. Physiol.82(3): 772–775, 1997.—This study investigated the effect of long-term intake of a fructose diet and exercise training on glycogen content in liver and skeletal muscle in female rats. Thirty-six rats (8 wk old) were divided into two dietary groups and were fed with a control (chow) diet or fructose diet (containing 20% fructose) for 12 wk. During this period, one-half of the rats in each dietary group were trained by using a motor-driven treadmill (running speed of 25 m/min and duration of 90 min/day, 5 days/wk). The liver glycogen was increased by intake of a fructose diet and exercise training, and the content was in the following order: control-diet and sedentary rats < fructose-diet and sedentary rats ≤ control-diet and trained rats < fructose-diet and trained rats in the ratio of 1:3.4:3.6:5.0. The glycogen content in gastrocnemius muscle showed the same trend as that in liver; the ratio was 1:1.3:1.3:1.6. These results indicate that both long-term intake of the fructose diet and exercise training synergistically increased glycogen in both tissues.

2009 ◽  
Vol 10 (4) ◽  
pp. 374-380 ◽  
Author(s):  
Pamela Johnson Rowsey ◽  
Bonnie L. Metzger ◽  
John Carlson ◽  
Christopher J. Gordon

Long-term exercise training selectively alters serum cytokines involved in fever. Chronic exercise training has a number of effects on the immune system that may mimic the physiological response to fever. Female rats that voluntarily exercise on running wheels develop an elevated daytime core temperature after several weeks of training. It remains to be seen whether the elevation in daytime temperature involves inflammatory patterns characteristic of an infectious fever. We assessed whether chronic exercise training in the rat would alter levels of cytokines involved in fever. Female Sprague Dawley rats at 45 days of age weighing 90—110 g were divided into two groups (exercise and sedentary) and housed at an ambient temperature of 22°C. Interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor alpha (TNF-α), iron, and zinc levels were analyzed. Rats underwent 8 weeks of exercise on running wheels. Exercise led to altered levels of some key cytokines that are involved in fever. Exercise animals had significantly higher IL-1β levels and lower IL-10 levels compared to sedentary animals. Although IL-6 levels were slightly lower in the exercise animals, these levels were not significantly affected by training. TNF-α activity was similar in the two groups. Training also led to a slight increase in serum zinc and decrease in serum unsaturated iron binding capacity (UIBC). The data suggest that chronic exercise training evokes immune responses that mimic some, but not all, aspects of fever. This may explain why exercise leads to elevated daytime core temperature.


2013 ◽  
Vol 305 (4) ◽  
pp. R423-R434 ◽  
Author(s):  
Justin D. La Favor ◽  
Ethan J. Anderson ◽  
Jillian T. Dawkins ◽  
Robert C. Hickner ◽  
Christopher J. Wingard

The aim of this study was to investigate aerobic exercise training as a means to prevent erectile dysfunction (ED) and coronary artery disease (CAD) development associated with inactivity and diet-induced obesity. Male Sprague-Dawley rats were fed a Western diet (WD) or a control diet (CD) for 12 wk. Subgroups within each diet remained sedentary (Sed) or participated in aerobic interval treadmill running throughout the dietary intervention. Erectile function was evaluated under anesthesia by measuring the mean arterial pressure and intracavernosal pressure in response to electrical field stimulation of the cavernosal nerve, in the absence or presence of either apocynin, an NADPH oxidase inhibitor, or sepiapterin, a tetrahydrobiopterin precursor. Coronary artery endothelial function (CAEF) was evaluated ex vivo with cumulative doses of ACh applied to preconstricted segments of the left anterior descending coronary artery. CAEF was assessed in the absence or presence of apocynin or sepiapterin. Erectile function ( P < 0.0001) and CAEF ( P < 0.001) were attenuated in WD-Sed. Exercise preserved erectile function ( P < 0.0001) and CAEF ( P < 0.05) within the WD. Erectile function ( P < 0.01) and CAEF ( P < 0.05) were augmented by apocynin only in WD-Sed, while sepiapterin ( P < 0.05) only augmented erectile function in WD-Sed. These data demonstrate that a chronic WD induces impairment in erectile function and CAEF that are commonly partially reversible by apocynin, whereas sepiapterin treatment exerted differential functional effects between the two vascular beds. Furthermore, exercise training may be a practical means of preventing diet-induced ED and CAD development.


2016 ◽  
Vol 60 (1) ◽  
pp. 28536 ◽  
Author(s):  
Noemi A. V. Roza ◽  
Luiz F. Possignolo ◽  
Adrianne C. Palanch ◽  
José A. R. Gontijo

1989 ◽  
Vol 256 (4) ◽  
pp. H1110-H1116 ◽  
Author(s):  
D. C. Poole ◽  
O. Mathieu-Costello ◽  
J. B. West

The total capillary length available for blood-tissue transfer is determined by the number and orientation of the capillaries. Therefore, whether capillary tortuosity changes with exercise training has important implications for peripheral gas exchange. To determine the effects of exercise training on capillary orientation and capillary length per volume of muscle fiber [Jv(c,f)] female rats were trained by treadmill running (30 m/min, up to 60 min/day, 5 days/wk) for 4 wk. Muscles from control and trained rats were perfusion fixed at sarcomere lengths (l) ranging from 1.59 to 2.15 microns, and morphometric techniques were used to estimate capillary orientation and Jv(c,f). Training increased (P less than 0.05) musculus soleus oxidative capacity 35% [as estimated from citrate synthase activity: 24.7 +/- 1.4 to 34.7 +/- 1.0 (SE) mumol.g-1.min-1], capillary-to-fiber ratio 30% (2.17 +/- 0.06 to 2.83 +/- 0.05), and Jv(c,f) 32% (1,886 +/- 73 to 2,496 +/- 180 mm-2). Capillary tortuosity (as determined from comparisons of transverse and longitudinal sections) was a direct function of l in control and trained rats and contributed 17-73% of capillary length above that estimated from capillary counts on transverse sections. We conclude that capillary tortuosity in m. soleus is unchanged by training. Therefore, Jv(c,f) increases as a consequence of increased capillary number. M. soleus citrate synthase activity is best correlated with Jv(c,f) and not with capillary counts on transverse sections. We hypothesize that training-induced muscle changes of capillary geometry improve O2 delivery to skeletal muscle and may therefore alter the metabolic response (e.g., lactate accumulation) to exercise after training.(ABSTRACT TRUNCATED AT 250 WORDS)


1987 ◽  
Vol 252 (2) ◽  
pp. E170-E175
Author(s):  
G. L. Dohm ◽  
M. K. Sinha ◽  
J. F. Caro

Exercise has been shown to increase insulin sensitivity, and muscle is quantitatively the most important tissue of insulin action. Since the first step in insulin action is the binding to a membrane receptor, we postulated that exercise training would change insulin receptors in muscle and in this study we have investigated this hypothesis. Female rats initially weighing approximately 100 g were trained by treadmill running for 2 h/day, 6 days/wk for 4 wk at 25 m/min (0 grade). Insulin receptors from vastus intermedius muscles were solubilized by homogenizing in a buffer containing 1% Triton X-100 and then partially purified by passing the soluble extract over a wheat germ agglutinin column. The 4 wk training regimen resulted in a 65% increase in citrate synthase activity in red vastus lateralis muscle, indicating an adaptation to exercise. Insulin binding by the partially purified receptor preparation s was approximately doubled in muscle of trained rats at all insulin concentrations, suggesting an increase in the number of receptors. Training did not alter insulin receptor structure as evidenced by electrophoretic mobility under reducing and nonreducing conditions. Basal insulin receptor protein kinase activity was higher in trained than untrained animals and this was likely due to the greater number of receptors. However, insulin stimulation of the protein kinase activity was depressed by training. These results demonstrate that endurance training does alter receptor number and function in muscle and these changes may be important in increasing insulin sensitivity after exercise training.


2013 ◽  
Vol 28 (10) ◽  
pp. 2464-2476 ◽  
Author(s):  
C. S. Pinhal ◽  
A. Lopes ◽  
D. B. Torres ◽  
S. L. Felisbino ◽  
J. A. Rocha Gontijo ◽  
...  

1983 ◽  
Vol 31 (1) ◽  
pp. 133-135 ◽  
Author(s):  
James O. Hill ◽  
James R. Davis ◽  
Anthony R. Tagliaferro

2006 ◽  
Vol 291 (5) ◽  
pp. E906-E912 ◽  
Author(s):  
Pietro Lucotti ◽  
Emanuela Setola ◽  
Lucilla D. Monti ◽  
Elena Galluccio ◽  
Sabrina Costa ◽  
...  

Because chronic l-arginine supplementation improves insulin sensitivity and endothelial function in nonobese type 2 diabetic patients, the aim of this study was to evaluate the effects of a long-term oral l-arginine therapy on adipose fat mass (FM) and muscle free-fat mass (FFM) distribution, daily glucose levels, insulin sensitivity, endothelial function, oxidative stress, and adipokine release in obese type 2 diabetic patients with insulin resistance who were treated with a combined period of hypocaloric diet and exercise training. Thirty-three type 2 diabetic patients participated in a hypocaloric diet plus an exercise training program for 21 days. Furthermore, they were divided into two groups in randomized order: the first group was also treated with l-arginine (8.3 g/day), and the second group was treated with placebo. Although in the placebo group body weight, waist circumference, daily glucose profiles, fructosamine, insulin, and homeostasis model assessment index significantly decreased, l-arginine supplementation further decreased FM ( P < 0.05) and waist circumference ( P < 0.0001), preserving FFM ( P < 0.03), and improved mean daily glucose profiles ( P < 0.0001) and fructosamine ( P < 0.03). Moreover, change in area under the curve of cGMP (second messenger of nitric oxide; P < 0.001), superoxide dismutase (index of antioxidant capacity; P < 0.01), and adiponectin levels ( P < 0.02) increased, whereas basal endothelin-1 levels ( P < 0.01) and leptin-to-adiponectin ratio ( P < 0.05) decreased in the l-arginine group. Long-term oral l-arginine treatment resulted in an additive effect compared with a diet and exercise training program alone on glucose metabolism and insulin sensitivity. Furthermore, it improved endothelial function, oxidative stress, and adipokine release in obese type 2 diabetic patients with insulin resistance.


2000 ◽  
Vol 88 (2) ◽  
pp. 433-442 ◽  
Author(s):  
J. David Symons ◽  
Stephen V. Rendig ◽  
Charles L. Stebbins ◽  
John C. Longhurst

We hypothesized that exercise training preserves endothelium-dependent relaxation, lessens receptor-mediated constriction of coronary resistance arteries, and reduces myocardial contractile dysfunction in response to ischemia. After 10 wk of treadmill running or cage confinement, regional and global indexes of left ventricular contractile function were not different between trained and sedentary animals in response to three 15-min periods of ischemia (long-term; n = 17), one 5-min bout of ischemia (short-term; n = 18), or no ischemia (sham-operated; n = 24). Subsequently, coronary resistance vessels (∼106 ± 4 μm ID) were isolated and studied using wire myographs. Maximal ACh-evoked relaxation was ∼25, 40, and 60% of KCl-induced preconstriction after the long-term, short-term, and sham-operated protocols, respectively, and was similar between groups. Maximal sodium nitroprusside-evoked relaxation also was similar between groups among all protocols, and vasoconstrictor responses to endothelin-1 and U-46619 were not different in trained and sedentary rats after short-term ischemia or sham operation. We did observe that, after long-term ischemia, maximal tension development in response to endothelin-1 and U-46619 was blunted ( P < 0.05) in trained animals by ∼70 and ∼160%, respectively. These results support our hypothesis that exercise training lessens receptor-mediated vasoconstriction of coronary resistance vessels after ischemia and reperfusion. However, training did not preserve endothelial function of coronary resistance vessels, or myocardial contractile function, after ischemia and reperfusion.


2009 ◽  
Vol 296 (5) ◽  
pp. R1557-R1563 ◽  
Author(s):  
Tomonori Ogata ◽  
Yasuharu Oishi ◽  
Kazuhiko Higashida ◽  
Mitsuru Higuchi ◽  
Isao Muraoka

Skeletal muscle may develop adaptive molecular chaperone enhancements as a potential defense system through repeated daily exercise stimulation. The present study investigated whether prolonged exercise training alters the expression of molecular chaperone proteins for the long term in skeletal muscle. Mature male Wistar rats were subjected for 8 wk to either a single bout of acute intermittent treadmill running (30 m/min, 5 min × 4, 5° grade) or prolonged treadmill running training (15–40 m/min, 5 min × 4, 5–7° grade). Levels of five molecular chaperone proteins [heat shock protein (HSP)25, HSP60, glucose-regulated protein (GRP)78, HSP70, and heat shock cognate (HSC)70] were measured in response to acute exercise and prolonged training. HSP70 levels were increased 6 and 24 h after acute exercise, but expression returned to control level within 2 days. In contrast, prolonged training had a long-term effect on HSP70 expression. Levels of HSP70 were notably increased by 4.5-fold over control 2 days after prolonged training; the enhancement was maintained for at least 14 days after training ended. However, other molecular chaperone proteins did not show adaptive changes in response to prolonged training. In addition, HSP70 enhancement by prolonged exercise training was not accompanied by transcription of HSP70 mRNA. These findings demonstrate that prolonged training can induce long-term enhancement of HSP70 expression without change at the mRNA level in skeletal muscle.


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