scholarly journals Transient enhancement of GLUT-4 levels in rat epitrochlearis muscle after exercise training

2000 ◽  
Vol 88 (6) ◽  
pp. 2240-2245 ◽  
Author(s):  
Thomas H. Reynolds ◽  
Joseph T. Brozinick ◽  
Lisa M. Larkin ◽  
Samuel W. Cushman
Keyword(s):  
Exercise Training ◽  
Protein Content ◽  
Glucose Transport ◽  
Skeletal Muscles ◽  
Transport Activity ◽  
Short Term ◽  
Glut 4 ◽  
Glucose Transport System ◽  
Female Wistar Rats

The purpose of the present study was to examine the effect of detraining on the glucose transport system after short-term swim training (5 days), long-term swim training (5 wk), and treadmill run training (5 wk). Skeletal muscles were isolated from female Wistar rats at 24 or 48 h posttraining. SST produces a 48% increase in GLUT-4 mRNA, a 30% increase in GLUT-4 protein, and a 60% increase in insulin-stimulated glucose transport activity at 24 h posttraining but not at 48 h posttraining. Similar to SST, long-term swim training produces a 60% increase in GLUT-4 mRNA and a 30% increase in GLUT-4 protein content at 24 h posttraining but not at 48 h posttraining. Finally, treadmill run training produces a transient 35% increase in GLUT-4 protein content that is completely reversed at 48 h after the last bout of exercise. These results demonstrate that the increase in GLUT-4 mRNA and GLUT-4 protein occurs during the first week of exercise training and is rapidly lost after training cessation. We believe that the transient enhancement in GLUT-4 protein after exercise training is due to a short GLUT-4 half-life, a process that is primarily regulated by pretranslational mechanisms.

Short-term exercise enhances insulin-stimulated GLUT-4 translocation and glucose transport in adipose cells

1998 ◽  
Vol 85 (6) ◽  
pp. 2106-2111 ◽  
Author(s):  
Cynthia M. Ferrara ◽  
Thomas H. Reynolds ◽  
Mary Jane Zarnowski ◽  
Joseph T. Brozinick ◽  
Samuel W. Cushman
Keyword(s):  
Exercise Training ◽  
Cell Surface ◽  
Glucose Transport ◽  
Transport Activity ◽  
Short Term ◽  
Adipose Cell ◽  
Glut 4 ◽  
Glut 4 Translocation ◽  
Adipose Cell Size ◽  
Adipose Cells

This investigation examined the effects of short-term exercise training on insulin-stimulated GLUT-4 glucose transporter translocation and glucose transport activity in rat adipose cells. Male Wistar rats were randomly assigned to a sedentary (Sed) or swim training group (Sw, 4 days; final 3 days: 2 × 3 h/day). Adipose cell size decreased significantly but minimally (∼20%), whereas total GLUT-4 increased by 30% in Sw vs. Sed rats. Basal 3- O-methyl-d-[14C]glucose transport was reduced by 62%, whereas maximally insulin-stimulated (MIS) glucose transport was increased by 36% in Sw vs. Sed rats. MIS cell surface GLUT-4 photolabeling was 44% higher in the Sw vs. Sed animals, similar to the increases observed in MIS glucose transport activity and total GLUT-4. These results suggest that increases in total GLUT-4 and GLUT-4 translocation to the cell surface contribute to the increase in MIS glucose transport with short-term exercise training. In addition, the results suggest that the exercise training-induced adaptations in glucose transport occur more rapidly than previously thought and with minimal changes in adipose cell size.

Glucose transporters and glucose transport in skeletal muscles of 1- to 25-mo-old rats

1993 ◽  
Vol 264 (3) ◽  
pp. E319-E327 ◽  
Author(s):  
E. A. Gulve ◽  
E. J. Henriksen ◽  
K. J. Rodnick ◽  
J. H. Youn ◽  
J. O. Holloszy
Keyword(s):  
Glucose Transport ◽  
Skeletal Muscles ◽  
Glucose Transporter ◽  
Contractile Activity ◽  
Transport Activity ◽  
Glut 4 ◽  
Flexor Digitorum Brevis ◽  
Old Rats ◽  
Growth And Aging ◽  
Flexor Digitorum

It is widely thought that aging results in development of insulin resistance in skeletal muscle. In this study, we examined the effects of growth and aging on the concentration of the GLUT-4 glucose transporter and on glucose transport activity in skeletal muscles of female Long-Evans rats. Relative amounts of immunoreactive GLUT-4 protein were measured in muscle homogenates of 1-, 10-, and 25-mo-old rats by immunoblotting with a polyclonal antibody directed against GLUT-4. In the epitrochlearis, plantaris, and the red and white regions of the quadriceps muscles, GLUT-4 immunoreactivity decreased by 14-33% between 1 and 10 mo of age and thereafter remained constant. In flexor digitorum brevis (FDB) and soleus muscles, GLUT-4 concentration was similar at all three ages studied. Glucose transport activity was assessed in epitrochlearis and FDB muscles by incubation with 2-deoxyglucose under the following conditions: basal, submaximal insulin, and either maximal insulin or maximal insulin combined with contractile activity. Glucose transport in the epitrochlearis muscle decreased by approximately 60% between 1 and 4 mo of age and then did not decline further between 4 and 25 mo of age. Transport activity in the FDB assessed with a maximally effective insulin concentration decreased only slightly (< 20%) between 1 and 7 mo of age. Aging, i.e., the transition from young adulthood to old age, was not associated with a decrease in glucose transport activity in either the epitrochlearis or the FDB.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucose transporter protein content and glucose transport capacity in rat skeletal muscles

1990 ◽  
Vol 259 (4) ◽  
pp. E593-E598 ◽  
Author(s):  
E. J. Henriksen ◽  
R. E. Bourey ◽  
K. J. Rodnick ◽  
L. Koranyi ◽  
M. A. Permutt ◽  
...  
Keyword(s):  
Protein Content ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Contractile Activity ◽  
Fiber Type ◽  
Linear Regression Analysis ◽  
Type I ◽  
Fiber Types ◽  
Transport Activity ◽  
Glut 4

The relationships among fiber type, glucose transporter (GLUT-4) protein content, and glucose transport activity stimulated maximally with insulin and/or contractile activity were studied by use of the rat epitrochlearis (15% type I-20% type II2a-65% type IIb), soleus (84-16-0%), extensor digitorum longus (EDL, 3-57-40%), and flexor digitorum brevis (FDB, 7-92-1%) muscles. Insulin-stimulated 2-deoxy-D-glucose (2-DG) uptake was greatest in the soleus, followed (in order) by the FDB, EDL, and epitrochlearis. On the other hand, contractile activity induced the greatest increase in 2-DG uptake in the FDB, followed by the EDL, soleus, and epitrochlearis. The effects of insulin and contractile activity on 2-DG uptake were additive in all the muscle preparations, with the relative rates being FDB greater than soleus greater than EDL greater than epitrochlearis. Quantitation of the GLUT-4 protein content with the antiserum R820 showed the following pattern: FDB greater than soleus greater than EDL greater than epitrochlearis. Linear regression analysis showed that whereas a relatively low and nonsignificant correlation existed between GLUT-4 protein content and 2-DG uptake stimulated by insulin alone, significant correlations existed between GLUT-4 protein content and 2-DG uptake stimulated either by contractions alone (r = 0.950) or by insulin and contractions in combination (r = 0.992). These results suggest that the differences in maximally stimulated glucose transport activity among the three fiber types may be related to differences in their content of GLUT-4 protein.

Effects of exercise training on glucose transport and cell surface GLUT-4 in isolated rat epitrochlearis muscle

1997 ◽  
Vol 272 (2) ◽  
pp. E320-E325 ◽  
Author(s):  
T. H. Reynolds ◽  
J. T. Brozinick ◽  
M. A. Rogers ◽  
S. W. Cushman
Keyword(s):  
Exercise Training ◽  
Cell Surface ◽  
Glucose Transport ◽  
Muscle Glycogen ◽  
Citrate Synthase ◽  
Transport Activity ◽  
Glut 4 ◽  
Isolated Rat

The effects of exercise training on maximal glucose transport activity and cell surface GLUT-4 were examined in rat epitrochlearis muscle. Five days of swim training (2 x 3 h/day) produce a significant increase in citrate synthase activity (24.5 +/- 0.6 vs. 20.1 +/- 0.7 micromol x min(-1) x g(-1)), GLUT-4 content (22.9 +/- 0.8 vs. 17.4 +/- 0.4% GLUT-4 standard), and glycogen levels (54.3 +/- 9.4 vs. 28.6 +/- 9.4 micromol/g). Maximally, insulin-stimulated glucose transport activity and cell surface GLUT-4 are increased by 55 (1.50 +/- 0.11 vs. 0.97 +/- 0.10 micromol x ml(-1) x 20 min(-1)) and 48% [12.0 +/- 0.8 vs. 8.1 +/- 0.9 disintegrations x min(-1) (dpm) x mg(-1)], respectively, in exercise-trained epitrochlearis muscles. In contrast, hypoxia-stimulated glucose transport activity and cell surface GLUT-4 are reduced by 38 (0.78 +/- 0.08 vs.1.25 +/- 0.14 micromol x ml(-1) x 20 min(-1)) and 40% (5.7 +/- 0.9 vs. 9.4 +/- 1.2 dpm/mg), respectively, in exercise-trained epitrochlearis muscles. These results demonstrate that changes in insulin- and hypoxia-stimulated glucose transport activity after exercise training are fully accounted for by the appearance of cell surface GLUT-4 and support the concept of two intracellular pools of GLUT-4. Finally, we propose that high levels of muscle glycogen with exercise training may contribute to the decrease in hypoxia-stimulated glucose transport activity.

scholarly journals Mechanism of hypoxia-stimulated glucose transport in rat skeletal muscle: potential role of glycogen

1998 ◽  
Vol 274 (5) ◽  
pp. E773-E778 ◽  
Author(s):  
Thomas H. Reynolds ◽  
Joseph T. Brozinick ◽  
M. A. Rogers ◽  
Samuel W. Cushman
Keyword(s):  
Exercise Training ◽  
Glucose Transport ◽  
Potential Role ◽  
Transport Activity ◽  
Glut 4 ◽  
Selective Targeting ◽  
Transport Response ◽  
Muscle Glucose Transport ◽  
Strong Inverse Relationship

We have previously reported that exercise training is associated with enhanced insulin-stimulated glucose transport activity and inhibited hypoxia-stimulated glucose transport activity in rat epitrochlearis muscle. Here we examine the potential role of muscle glycogen in the inhibited glucose transport response to hypoxia. Three days of swim training (2 × 3 h/day) produce a 100% increase in glycogen and a 70% increase in GLUT-4 in epitrochlearis muscle. Glucose transport after 1 h of hypoxia in muscles from fed exercise-trained (ET) rats is not significantly elevated above basal and is 40% lower than that in muscles from fed sedentary (SED) rats. Glycogen levels after 1 h of hypoxia are reduced by 27 and 64% in muscles from fed ET and fed SED rats, respectively. After 2 h of hypoxia, glucose transport is significantly increased above basal in muscles from fed ET rats, but this response is still 55% lower than that in muscles from fed SED rats. After 2 h of hypoxia, glycogen is reduced by 50 and 83% in muscles from fed ET and fed SED rats, respectively. After a modified overnight fast (≈4.5 g of chow), the glucose transport and glycogen responses to 1 h of hypoxia are not significantly different between muscles from ET and SED rats. These findings demonstrate a strong inverse relationship between glycogen and hypoxia-stimulated glucose transport activity and that high levels of glycogen contribute to the inhibited glucose transport response to hypoxia. Furthermore, failure of the overexpression of GLUT-4 after exercise training to enhance the glucose transport response to contraction/hypoxia suggests selective targeting of the additional GLUT-4 to the insulin-responsive pool.

Effects of exercise training on skeletal muscle glucose uptake and transport

1993 ◽  
Vol 264 (3) ◽  
pp. C727-C733 ◽  
Author(s):  
G. J. Etgen ◽  
J. T. Brozinick ◽  
H. Y. Kang ◽  
J. L. Ivy
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Glucose Uptake ◽  
Protein Content ◽  
Glucose Transport ◽  
Exercise Session ◽  
Rat Skeletal Muscle ◽  
Glut 4 ◽  
Skeletal Muscle Glucose Uptake ◽  
Uptake And Transport

Exercise training increases the concentration of GLUT-4 protein in skeletal muscle that is associated with an increase in maximal insulin-stimulated glucose transport. The purpose of this study was to determine whether exercise training results in a long-lasting increase in insulin-stimulated glucose transport in rat skeletal muscle. Glucose uptake and skeletal muscle 3-O-methyl-D-glucose (3-MG) transport were determined during hindlimb perfusion in the presence of a maximally stimulating concentration of insulin (10 mU/ml). Hindlimb glucose uptake was approximately 29% above sedentary (Sed) levels in rats examined within 24 h (24H) of their last exercise session. However, when rats were examined 48 h (48H) after their last exercise session, hindlimb glucose uptake was not different from Sed levels. Maximal 3-MG transport was enhanced, above Sed levels, in red (RG; 72% increase) and white (WG; 44% increase) gastrocnemius and plantaris (Plan; 67% increase) muscles, but not soleus (Sol), of 24H rats. GLUT-4 protein content was significantly elevated in those muscles that exhibited enhanced 3-MG transport in 24H rats. GLUT-4 protein content was also elevated in RG, WG, and Plan of 48H rats and was not different from 24H rats. Despite the elevated GLUT-4 protein content, 3-MG transport in 48H rats was only slightly, although statistically not significantly, higher than in Sed rats. These results provide evidence that exercise training does not result in a persistent increase in skeletal muscle glucose uptake or transport, despite an increase in GLUT-4 protein content.

Seven days of exercise increase GLUT-4 protein content in human skeletal muscle

1995 ◽  
Vol 79 (6) ◽  
pp. 1936-1938 ◽  
Author(s):  
J. A. Houmard ◽  
M. S. Hickey ◽  
G. L. Tyndall ◽  
K. E. Gavigan ◽  
G. L. Dohm
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Protein Content ◽  
Human Skeletal Muscle ◽  
Glucose Transporter ◽  
Vastus Lateralis ◽  
Cycle Ergometer ◽  
Maximal Heart Rate ◽  
Short Term ◽  
Glut 4

Insulin-responsive glucose transporter (GLUT-4) content increases by 1.8-fold in skeletal muscle with 14 wk of exercise training [Houmard et al. Am. J. Physiol. 264 (Endocrinol. Metab. 27): E896-E901, 1993]. The purpose of this study was to determine whether more short-term training (7 days) increases GLUT-4 protein content in human skeletal muscle. Seven sedentary men [25.0 +/- 1.1 (SE) yr, 44.1 +/- 2.2 ml.kg-1.min-1 maximal O2 uptake, 14.9 +/- 2.1% body fat] were examined before and after 7 days of cycle ergometer training (1 h/day, 76 +/- 2% maximal heart rate). Needle biopsy samples from the vastus lateralis were used to determine GLUT-4 protein content. Muscle GLUT-4 increased (P < 0.05) by an average of 2.8 +/- 0.5-fold with 7 days of training. GLUT-4 content in skeletal muscle thus increases substantially with short-term exercise training.

Effects of high-intensity swimming training on GLUT-4 and glucose transport activity in rat skeletal muscle

2001 ◽  
Vol 90 (6) ◽  
pp. 2019-2024 ◽  
Author(s):  
Shin Terada ◽  
Toshiko Yokozeki ◽  
Kentaro Kawanaka ◽  
Kishiko Ogawa ◽  
Mitsuru Higuchi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Weight ◽  
Exercise Training ◽  
Glucose Transport ◽  
High Intensity ◽  
Prolonged Exercise ◽  
Intermittent Exercise ◽  
Transport Activity ◽  
Rat Skeletal Muscle ◽  
Glut 4

This study was performed to assess the effects of short-term, extremely high-intensity intermittent exercise training on the GLUT-4 content of rat skeletal muscle. Three- to four-week-old male Sprague-Dawley rats with an initial body weight ranging from 45 to 55 g were used for this study. These rats were randomly assigned to an 8-day period of high-intensity intermittent exercise training (HIT), relatively high-intensity intermittent prolonged exercise training (RHT), or low-intensity prolonged exercise training (LIT). Age-matched sedentary rats were used as a control. In the HIT group, the rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 2, the next 4, and the last 2 days, respectively. Between exercise bouts, a 10-s pause was allowed. RHT consisted of five 17-min swimming bouts with a 3-min rest between bouts. During the first bout, the rat swam without weight, whereas during the following four bouts, the rat was attached to a weight equivalent to 4 and 5% of its body weight for the first 5 days and the following 3 days, respectively. Rats in the LIT group swam 6 h/day for 8 days in two 3-h bouts separated by 45 min of rest. In the first experiment, the HIT, LIT, and control rats were compared. GLUT-4 content in the epitrochlearis muscle in the HIT and LIT groups after training was significantly higher than that in the control rats by 83 and 91%, respectively. Furthermore, glucose transport activity, stimulated maximally by both insulin (2 mU/ml) (HIT: 48%, LIT: 75%) and contractions (25 10-s tetani) (HIT: 55%, LIT: 69%), was higher in the training groups than in the control rats. However, no significant differences in GLUT-4 content or in maximal glucose transport activity in response to both insulin and contractions were observed between the two training groups. The second experiment demonstrated that GLUT-4 content after HIT did not differ from that after RHT (66% higher in trained rats than in control). In conclusion, the present investigation demonstrated that 8 days of HIT lasting only 280 s elevated both GLUT-4 content and maximal glucose transport activity in rat skeletal muscle to a level similar to that attained after LIT, which has been considered a tool to increase GLUT-4 content maximally.

Exercise training reverses insulin resistance in muscle by enhanced recruitment of GLUT-4 to the cell surface

1997 ◽  
Vol 272 (5) ◽  
pp. E864-E869 ◽  
Author(s):  
G. J. Etgen ◽  
J. Jensen ◽  
C. M. Wilson ◽  
D. G. Hunt ◽  
S. W. Cushman ◽  
...  
Keyword(s):  
Exercise Training ◽  
Cell Surface ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Zucker Rat ◽  
Transport Activity ◽  
Glut 4 ◽  
Obese Zucker Rat ◽  
Slow Twitch ◽  
Fast Twitch

The effects of exercise training on cell surface GLUT-4 in skeletal muscle of the obese (fa/fa) Zucker rat were investigated using the impermeant glucose transporter photoaffinity reagent 2-N-4-(1-azi-2,2,2-trifluoroethyl)-benzoyl-1,3-bis- (D-mannos-4-yloxy)-2-propylamine (ATB-BMPA). In the absence of insulin, 3-O-methyl-D-glucose transport activity was no different in either fast-twitch (epitrochlearis) or slow-twitch (soleus) muscles of trained and sedentary obese rats. Likewise, basal ATB-BMPA-labeled GLUT-4 was not altered in these muscles with training. In contrast, the trained group exhibited significantly greater insulin-stimulated (2 mU/ml) glucose transport activity in epitrochlearis muscles than the sedentary group (0.53 +/- 0.03 vs. 0.18 +/- 0.03 mumol.g-1 x 10 min-1 for trained and sedentary, respectively), which was paralleled by a significant enhancement of insulin-stimulated cell surface GLUT-4 (5.33 +/- 0.20 vs. 1.57 +/- 0.14 disintegrations.min-1.mg-1 for trained and sedentary, respectively). Exercise training, however, did not alter insulin-stimulated glucose transport activity or cell surface GLUT-4 in soleus muscles. Finally, exercise training did not alter the ability of muscle contraction to elevate glucose transport activity or cell surface GLUT-4 in either epitrochlearis or soleus muscles of the obese rat. These results indicate that training improves insulin-stimulated glucose transport in muscle of the obese Zucker rat by increasing GLUT-4 content and by altering the normal intracellular distribution of these transporters such that they are now capable of migrating to the cell surface in response to the insulin stimulus.

Exercise training prevents maturation-induced decrease in insulin sensitivity

1996 ◽  
Vol 80 (6) ◽  
pp. 1963-1967 ◽  
Author(s):  
N. Nakai ◽  
Y. Shimomura ◽  
N. Ohsaki ◽  
J. Sato ◽  
Y. Oshida ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Exercise Training ◽  
Infusion Rate ◽  
Glucose Transporter ◽  
Euglycemic Clamp ◽  
Glut 4 ◽  
Hindlimb Muscle ◽  
Female Wistar Rats ◽  
Sensitivity Improvement

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.

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