• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.377-382
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• 2003

This study investigated the effects of green tea on the muscle antioxidative defense system in the white & red gastrocnemius muscles of rats after aerobic exercise. Male Sprague-Dawley rats weighing 150 10 g were randomly assigned to a control group, non-exercise with green tea group (G group), and exercise training group. The exercise training group was then further classified as the training (T) group and training with green tea (TG) group, the latter of which was supplemented with green tea in the drinking water during the experimental period. The rats in the exercise training groups (T and TG) were subjected to aerobic exercise on a treadmill 30 min/day at a speed of 28 m/min (7% incline) 5 days/week, while the other groups (control and G group) were cage confined for 4 weeks. Thereafter, the rats were sacrificed with an injected overdose of pentobarbital just after running. In the white muscle, the xanthine oxidase (XOD) activities were 71 % higher in the T group compared to control group, whereas the TG group had the same activity as the control group. The XOD activities in the red gastrocnemius muscle exhibited the same tendency as in the white muscle. The superoxide dismutase (SOD) activity in the white muscle was lower in the T group compared with the control group, yet significantly higher in the TG group compared with the T group. The SOD activities in the red gastrocnemius muscle exhibited the same tendency as in the white gastrocnemius muscle. The glutathione peroxidase (GSHpx) activities in the white & red gastrocnemius muscles were 43 % lower in the T group compared with the control group, yet the activities in the TG group remained at control levels. The glutathione S-transferase (GST) activity in the white muscle was not significantly different among any of the three groups, but in the red gastrocnemius muscle, the TG group had the same activity as in the control group. The thiobarbituric acid reactive substance (TBARS) contents in the white & red gastrocnemius muscles were higher in the T group than in the control but the control and TG groups had the same concentrations of TBARS. In conclusion, the supplementation of green tea in rats subjected to aerobic exercise was found to reduce the peroxidation of muscle lipids by enhancing the antioxidative defense mechanism.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.231-236
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• 1996

In our previous study (Kim et al, 1991), GLUT 4 protein content correlated negatively with plasma glucose levels in skeletal muscles of STZ-induced diabetic rats. Thus, in this study, to confirm whether expression of GLUT 4 correlate negatively with degree of hyperglycemia, we measured levels of GLUT 4 mRNA in red and white gastrocnemius muscles in STZ-induced mild and severe diabetic rats. Rats were randomly assigned to control, mild, and severe diabetic groups, and the diabetes was induced by intraperitoneal administration of STZ. The experiment was carried out 10 days after STZ administration. Gastrocnemius red and white muscles were used fur the measurement of GLUT 4 expression. Plasma glucose levels of mild and severe diabetic rats were increased compared to control rats (control, mild, and severe diabetes; $6.4{\pm}0.32,\;9.4{\pm}0.68,\;and\;22.0{\pm}0.58$ mmol/L, respectively). Plasma insulin levels of mild and severe diabetic rats were decreased compared to control rats (control, mild, and severe diabetes; $198{\pm}37,\;l14{\pm}14,\;and\;90{\pm}15$ pmol/L, respectively). GLUT 4 mRNA levels of gastrocnemius red muscles in mild and severe diabetic rats were decreased compared to control rats ($64{\pm}1.2%\;and\;71{\pm}2.0%$ of control, respectively), but GLUT 4 mRNA levels in gastrocnemius white muscles were unaltered in diabetic rats. In summary, GLUT 4 mRNA levels were decreased in STZ-induced diabetic rats but did not correlated negatively with degree of hyperglycemia, and this result suggest that the regulatory mechanisms of decreased GLUT 4 mRNA levels are hypoinsulinemia and/or other metabolic factor but not hyperglycemia. And regulation of GLUT 4 expression in STZ-induced diabetes between red and white enriched skeletal muscles may be related to a fiber specific gene regulatory mechanism.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.5
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• pp.283-287
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• 2006

Although estrogen is known to playa role in fatty acid metabolism, it remains unclear whether fatty acid oxidation in mature female rats differs from fatty acid oxidation in peri-pubertal young rats. In this study, we measured fatty acid metabolism in the skeletal muscles and livers of 5 and 50 weeks old male and female rats. The rate of palmitate oxidation in the liver and gastrocnemius red in the 50-week-old female rats were elevated as compared to the 5-week-old females, whereas there were no differences in the male rats. The rate of palmitate oxidation in the gastrocnemius red was correlated inversely with intra-abdominal fat mass in the 5-week-old male and female rats, whereas the palmitate oxidation rate was positively correlated with fat mass in the liver and gastrocnemius red in the 50-week-old rats. HOMA-IR and plasma insulin levels were positively correlated with intra-abdominal fat mass in the pooled 50-week-old male and female rats, but this correlation was not apparent in 5-week-old rats. In summary, the rate of fatty acid oxidation measured in the middle-aged adult female rats was significantly higher than those measured in the peri-pubertal young female rats. This difference may be attributed to the influence of ovarian hormones.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.4
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• pp.207-210
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• 2003

Lipids play many structural and metabolic roles, and dietary fat has great impact on metabolism and health. Fatty acid oxidation rate is dependent on tissue types. However there has been no report on the relationship between the rate of fatty acid oxidation and carnitine transport system in outer mitochondrial membrane of many tissues. In this study, the rate of fatty acid oxidation and carnitine palmitoyltransferase (CPT) I activity in the carnitine transport system were measured to understand the metabolic characteristics of fatty acid in various tissues. Palmitic acid oxidation rate and CPT I activity in various tissues were measured. Tissues were obtained from the white and red skeletal muscles, heart, liver, kidney and brain of rats. The highest lipid oxidation rate was demonstrated in the cardiac muscle, and the lowest oxidation rate was in brain. Red gastrocnemius muscle followed to the cardiac muscle. Lipid oxidation rates of kidney, white gastrocnemius muscle and liver were similar, ranging from 101 to 126 DPM/mg/hr. CPT I activity in the cardiac muscle was the highest, red gastrocnemius muscle followed by liver. Brain tissue showed the lowest CPT I activity as well as lipid oxidation rate, although the values were not significantly different from those of kidney and white gastrocnemius muscle. Therefore, lipid oxidation rate was highly (p＜0.001) related to CPT I activity. Lipid oxidation rate is variable, depending on tissue types, and is highly (p＜0.001) related to CPT I activity. CPT I activity may be a good marker to indicate lipid oxidation capacity in various tissues.

• Nutritional Sciences
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• v.6 no.3
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• pp.135-140
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• 2003

The purpose of this study was to investigate the effects of glucuyonic acid (isolated from xylan) on the antioxidative defense systems of red gastrocnemius in rats after aerobic exercise. The glucuronic acid was isolated from xylan. Male Sprague-Dawley vats weighing 150$\pm$10 g were randomly assigned to one normal group and three exercise training groups. The exercise training groups were classified as T (glucuronic acid-free diet), TU (250mg glucuronic acid/kg bw) and 2TU (500mg glucuronic acid /kg bw) according to the level of glucuvonic acid supplementation. The rats in the normal group were confined to a cage for 4 weeks. The rats in the exercise training groups ran on a treadmill for 30 min/day, 5 days/week at a speed of 28 m/min (7% incline) for 4 weeks. Glutamate oxaloacetate transaminase (GOT) activity in the exercise training groups increased significantly compared with that of the normal group. That of the TU and 2TU groups decreased significantly compared with that of the T group. Xanthine oxidase (XOD) activity in the T group increased significantly to 74% compared with that of the normal group. That of the 2TU group decreased to 42% compared with that of the T group, thus recovering to a normal level. Superoxide dismutase (SOD) activity in the T group decreased to 32% compared with that of the normal group. That of the TU and 2TU groups increased to 28% and 34%, respectively, compared with that of the T group. Glutathione peroxidase (GSHpx) activity in the T group decreased to 16% compared with that of the normal group, but that of the TU group increased to 17% compared with that of the T group. Glutathiones transferase (GST) activity in the T group decreased to 11% compared with that of the normal group, but that of the TU and 2TU groups Increased to 28% and 31%, respectively, compared with that of the T group. The contents of thiobarbituric acid reactive substances (TBARS) in the T group increased to 81% compared with that of the normal group, but the glucuronic supplementation group recovered to the normal level. In conclusio, the effects of glucuronic acid on red gastrocnemius in rats engaged in exercise training would appear to be to reduced lipid peroxidation of tissue as an antioxidative defense mechanism.

• Korean Journal of Exercise Nutrition
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• v.23 no.2
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• pp.1-6
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• 2019

[Purpose] Strenuous exercise often induces skeletal muscle damage, which results in impaired performance. Sphingolipid metabolism contributes to various cellular processes, including apoptosis, stress response, and inflammation. However, the relationship between exercise-induced muscle damage and ceramide (a key component of sphingolipid metabolism), is rarely studied. The present study aimed to explore the regulatory role of sphingolipid metabolism in exercise-induced muscle damage. [Methods] Mice were subjected to strenuous exercise by treadmill running with gradual increase in intensity. The blood and gastrocnemius muscles (white and red portion) were collected immediately after and 24 h post exercise. For 3 days, imipramine was intraperitoneally injected 1 h prior to treadmill running. [Results] Interleukin 6 (IL-6) and serum creatine kinase (CK) levels were enhanced immediately after and 24 h post exercise (relative to those of resting), respectively. Acidic sphingomyelinase (A-SMase) protein expression in gastrocnemius muscles was significantly augmented by exercise, unlike, serine palmitoyltransferase-1 (SPT-1) and neutral sphingomyelinase (N-SMase) expressions. Furthermore, imipramine (a selective A-SMase inhibitor) treatment reduced the exercise-induced CK and IL-6 elevations, along with a decrease in cleaved caspase-3 (Cas-3) of gastrocnemius muscles. [Conclusion] We found the crucial role of A-SMase in exercise-induced muscle damage.

• Nutritional Sciences
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• v.8 no.3
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• pp.181-188
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• 2005

We investigated the effects of diet manipulation on pro- and macro-glycogen accumulation and mobilization during exercise in different kinds of muscle fiber and tissue. Thirty-two Sprague-Dawley rats were divided into groups representing one of two dietary conditions: high fat (HF, n=16) or standard chow (CHOW, n=16). Each dietary group was fm1her divided into control (REST, n=8) and exercise (EXE, n=8). After an eight-week dietary intervention period, the animals in EXE swam for 3 hours while the animals in REST remained at rest Skeletal muscle (soleus, red gastrocnemius and white gastrocnemius) and liver samples were then dissected out and used for analyses. 1here was no statistical difference in body weight between the animals in the HF and mow groups (p>.05). Three hours of exercise significantly increased plasma free fatty acid (FFA) concentration in the animals in the CHOW group but not in the animals in the HF group. Both citrate. synthase (CS) and $\beta$-hydroxyacyl dehydrogenase ($\beta$-HAD) activities in skeletal muscles were higher in the HF group than in the mow group. CS and $\beta$-HAD activities were also the highest in red gastrocnemius and the lowest in white gastrocnemius. At both time points (i.e., rest and immediately after exercise) intramuscular triglyceride (IMTG) and liver TG concentrations were significantly higher in the HF compared to the CHOW. IMTG and liver TG changed selectively in the CHOW. Except in white gastrocnemius muscle, there was no significant difference in total glycogen content between HF and mow at rest. Although exercise significantly lowered total glycogen content in all groups and tissues (p<.05), the degree of reduction was markedly greater in the mow than in the HF. Whereas changes in proglycogen concentration showed a trend similar to those of total glycogen, alterations in macroglycogen concentrations clearly differed from those of total glycogen. Specifically, the degree of reduction of macroglycogen following three hours of exercise was substantially greater in the CHOW than in the HF. These results suggest that metabolic alterations induced by a long-term high fat diet may be caused by macro-glycogen rather than pro-glycogen.

• Journal of Yeungnam Medical Science
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• v.16 no.1
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• pp.34-42
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• 1999

The effects of hyperglycemia and hyperlipidemia on utilization of muscle glycogen during 45 minute Session of treadmill running(26 m/min, 8% grade) were evaluated using Sprague Dawley rats, and the characteristics of the 4 different type of muscles, I.e., soleus, white and red gastrocnemius, and plantaris, on glycogen utilization were simultaneously investigated. Hyperglycemia was induced by 145-165 mg/dL of oral glucose administration, and hyperlipidemia was induced by combined treatment of intraperitoneal heparine injection of 444 uEq/L and 10 % intralipose oral adminstration. During the hyperglycemic trial, the glycogen utilization of plantaris muscle was decreased by 13 % in 45 minute session of treadmill running compared to the control trial(p<0.05), and the glycogen utilization of white gastrocnemius was also decreased. The sparing tendency of glycogen was observed in soleus and red gastrocnemius by 5-13 % during 30 and 45 minute session of treadmill running in hyperglycemic trial. There was no glycogen sparing effect of hyperlipidemia in soleus, red gastrocnemius and plantaris muscle subjected in this experiment during exercise. However, only a slight sparing tendency of white gastrocnemius muscle was observed. In summary, the glycogen sparing effect of hyperglycemia during exercise was observed in plantaris and white gastrocnemius muscles in rats. However, there was no glycogen sparing effect of hyperlipidemia in the 4 hindlimb muscles. It was observed that the glycogen sparing effect of hyperglycemia is more prominent in fast glycolytic muscle fibers.

• Journal of Nutrition and Health
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• v.34 no.7
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• pp.748-753
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• 2001

This study is to investigate the effects of capsaicin with high-fat diet on tissue glycogen contents in exercise-trained rats. Forty male Sprague-Dawley rats were offered a high-fat diet for 2 wks in individual cages and were exercise-trained by a animal treadmill running throughout the experimental period. After 2 wks of the prefeeding with high-fat diet, the rats were divided into two group: high-fat diet group(CON)and high-fat diet + capsaicin(0.014%) group(CAP). The rats were killed by decapitation at 10 hr(rest), 1 hr and 2 hr after treadmill running(27m/min, 6$^{\circ}$). Body weight and epididymal adipose tissure weight were significantly lower in CAP than in CON, but soleus muscle weight was not different between the two groups. Glycogen contents in liver, soleus and gastrocnemius white muscles were significantly lower in CAP than in CON at rest, 1 hr and 2 hr (p<0.05). However, glycogen content in gastrocnemius red muscle was significantly higher in CAP compared with CON at 2 hr after the exercise(p<0.05). These results indicate that capsaicin intake with high-fat diet would decrease glycogen contents in liver and muscle, however, this effect on glycogen metabolism could be changed by muscle type.

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.137-154
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• 1997

The aim of the present investigation has, been to evaluate the depletion pattern of the supercompensated glycogen of hindlimb muscles during strenous exercise in rats. The plan of the maximizing muscle glycogen stores is based on the fact that a glycogen-depleted muscle by exercise will have an increased avidity for glycogen when exposed to a high carbohydrate diet. The glycogen concentration of soleus, red gastrocnemius and plantaris muscle, and liver was measured at 0, 30 and 60 minutes during treadmill exercise. The experimental animals were divided into 5 group - Normal(N), Control(C), 1Hour(1HR:after 1hour of glucose ingestion), 2Hour(2HR:after 2hour of glucose ingestion) and Exercise-1Hour(EX-1HR:glucose ingestion after 1 hour of preloading treadmill exercise)group - for glycogen storage study. The glycogen concentration of soleus, red gastrocnemius and plantaris muscles in N group was $4.57{\pm}0.34$, 5.11+0.24 and $6.55{\pm}0.20mg/gm\;wet\;wt.$, respectively. The glycogen concentration of soleus and red gastrocnemius in EX-1HR group were about 1.9 and 1.8 times than that of N group, respectively, but the concentration of plantaris was not higher than that of N group. The glycogen concentration of liver in N group was $41.0{\pm}1.47mg/gm\;wet\;wt.$ and the concentration of the overnight fasted C group was only 2.9% of the value of N group. The level of glycogen concentration of liver in the other glucose ingested groups(1HR, 2HR, including EX-1HR) was within 19 - 32% of that of N group. The blood glucose concentration of EX-1HR group was higher than that of N group, the plasma free fatty acid concentration of C and 2HR group was higher than that of N group, and the plasma insulin concentration of EX-1HR group was higher than that of N group. The concentrations of supercompensated glycogen of soleus and red gastrocnemius were rapidly decreased during 30 minutes of exercise but there was almost no changes of the concentration during the other 30 minutes of continuing exercise. The concentration of N group during 30 minutes of exercise was decreased but more slowly than those of EX-1HR group. The remaining level of glycogen after 60 minutes of exercise in EX-1HR group was higher than that of N group. Taken together, the mobilization of endogenous muscle glycogen at the first stage of exercise was proportioned to the initial level of glycogen concentration, and later on, when exercise continued, the muscle glycogen level was stabilized. And the remaining level of supercompensated muscle glycogen after 60 minutes of exercise was higher than that of normally stored glycogen level. The mobilization of the glycogen stroed in slow and fast oxidative muscle fibers is faster than in the fast glycolytic muscle fibers during strenous exercise.