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Purpose This study aimed to investigate the effects of acute cold stress (10℃, 0℃) compared with ordinary temperature (20℃) on exercise performance and physiological response at rest and during exercise. Methods A total of 10 healthy men (21.55 ± 2.16) were selected. In each environmental condition (20℃, 10℃, 0℃), the three testing order was randomly selected at crossover, and there was a week interval between the graded exercise test (GXT). On the testing day, they remained resting for 30 min in each environmental condition. Dependent variables (body temperature, energy metabolism parameters, skeletal muscle oxygenation profiles, and exercise performance parameters) were measured at rest and during GXT. Results In body temperature, at each environmental condition, there was a significant decrease (p

[Purpose] Lactate has several beneficial roles as an energy resource and in metabolism. However, studies on the effects of oral administration of lactate on fat metabolism and glycogen synthesis are limited. Therefore, the purpose of the present study was to investigate how oral administration of lactate affects fat metabolism and glycogen synthesis factors at specific times (0, 30, 60, 120 min) after intake. [Methods] Male Sprague Dawley (SD) rats (n = 24) were divided into four groups as follows: the control group (0 min) was sacrificed immediately after oral lactate administration; the test groups were administered lactate (2 g/kg) and sacrificed after 30, 60, and 120 min. Skeletal muscle and liver mRNA expression of GLUT4, FAT/CD36, PDH, CS, PC and GYS2 was assessed using reverse transcription-polymerase chain reaction. [Results] GLUT4 and FAT/CD36 expression was significantly increased in skeletal muscle 120 min after lactate administration. PDH expression in skeletal muscle was altered at 30 and 120 min after lactate consumption, but was not significantly different compared to the control. CS, PC and GYS2 expression in liver was increased 60 min after lactate administration. [Conclusion] Our results indicate that exogenous lactate administration increases GLUT4 and FAT/CD36 expression in the muscle as well as glycogen synthase factors (PC, GYS2) in the liver after 60 min. Therefore, lactate supplementation may increase fat utilization as well as induce positive effects on glycogen synthesis in athletes.

[Purpose] Blood glucose and insulin resistance were lower following hypoxic exposure in previous studies. However, the effect of hypoxia as therapy in obese model has not been unknown. [Methods] Six-week-old mice were randomly divided into chow diet (n=10) and high-fat diet (HFD) groups (n=20). The chow diet group received a non-purified commercial diet (65 % carbohydrate, 21 % protein, and 14 % fat) and water ad libitum. The HFD group was fed an HFD (Research Diet, #D12492; 60% kcal from fat, 5.24 kcal/g). Both groups consumed their respective diet for 7 weeks. Subsequently, HFD-induced mice (12-weeks-old) were randomly divided into two treatment groups : HFD-Normoxia (HFD; n=10) and HFD-Hypoxia (HYP; n=10, fraction of inspired=14.6%). After treatment for 4 weeks, serum glucose, insulin and oral glucose tolerance tests (OGTT) were performed. [Results] Homeostatic model assessment values for insulin resistance (HOMA-IR) of the HYP group tended to be lower than the HFD group. Regarding the OGTT, the area under the curve was 13% lower for the HYP group than the HFD group. [Conclusion] Insulin resistance tended to be lower and glucose uptake capacity was significantly augmented under hypoxia. From a clinical perspective, exposure to hypoxia may be a practical method of treating obesity.

[Purpose] This study aimed to investigate the effects of leucine-enriched essential amino acid (LEAA) supplementation on muscle fatigue and the level of inflammatory cytokines in wheelchair basketball players after a basketball game and interval training. [Methods] Of the ten recruited wheelchair basketball players (aged 34.5±8.9 years; lean body mass of 34.3±10.0 kg) who had spinal cord injury (SCI) and had undergone amputation, nine participated in the final test. These nine athletes received LEAA supplements (3 times 4.0 g/day) or placebo treatment in a double-blind, randomized, crossover study. We measured variables related to muscular fatigue and inflammatory response before the intense exercise and 4 days after recovery. [Results] The significant effect of LEAA supplementation was inhibition of circulating IL-6 levels in the LEAA-treated group compared with the placebo group (P < .05). However, no changes were observed in the TNF-α and creatinine kinase levels. Moreover, analysis of variance analysis showed no significant difference in the relative values of muscle soreness. However, the effect size analysis with Cohen’s d reported a significant improvement in the relative values of whole body and back muscle soreness. [Conclusion] Our results revealed that LEAA supplementation before and after intense exercise could help reduce muscle soreness and IL-6 levels in wheelchair basketball players.

In this study, we investigated the effects of exogenous lactate administration before exercise on energy substrate utilization during exercise. Mice were divided into exercise control (EX) and exercise with lactate intake (EXLA) groups, saline/lactate was administered 30 min before exercise. Respiratory gas was measured during moderate intensity treadmill exercise (30 min). Immediately after exercise, blood, liver, and skeletal muscle samples were collected and mRNA levels of energy metabolism-related and metabolic factors were analyzed. At 16–30 min of exercise, the respiratory exchange ratio (p = 0.045) and carbohydrate oxidation level (p = 0.014) were significantly higher in the EXLA than in the EX group. Immediately after exercise, the muscle and liver glycogen content and blood glucose level of the EXLA group were lower than those of the EX group. In addition, muscle mRNA levels of HK2 (hexokinase 2, p = 0.009), a carbohydrate oxidation-related factor, were higher in the EXLA than in the EX group, whereas the expression of PDK4 (pyruvate dehydrogenase kinase 4, p = 0.001), CS (citrate synthase, p = 0.045), and CD36 (cluster of differentiation 36, p = 0.002), factors related to oxidative metabolism, was higher in the EX than in the EXLA group. These results suggest that lactate can be used in various research fields to promote carbohydrate metabolism.

[Purpose] The purpose of this study was to determine whether different types of carbohydrate diets with or without exercise changes energy metabolism at rest and during exercise. [Methods] To minimize differences in food and energy intake between experimental groups, mice were pairfed. After 1 week of adaptation, 40 male ICR mice (6 weeks old) were randomly divided into four groups: Sta. (high fat + high starch), Scu. (high fat + high sucrose), StaEX. (high fat + high starch + exercise), and SucEX. (high fat + high sucrose + exercise). StaEX. and ScuEX. groups underwent training by running on a treadmill five times a week. After 10 weeks of training, energy metabolism was measured for 24 h and during a 1 h exercise period. [Results] The final body weight showed no significant difference between the groups. However, the weight of abdominal tissues (epididymal, perirenal, and mesenteric adipose tissue) in training groups was markedly decreased following 10 weeks of training. Results of all energy metabolism (24 h at rest and during 1 h of exercise) showed no significant interactions between diet and exercise. A brief summary of the results of the energy metabolism is that the metabolism related indicators over 24 h were more affected by the dietary pattern than the exercise but during the 1 h of exercise, training had more effect on energy metabolism than diet. [Conclusion] Our findings confirm that: (a) the type of carbohydrates included in the diet influence the metabolic responses over 24 h, (b) training had more effect on energy metabolism than diet during 1 h of exercise, (c) both results; abdominal adipose tissue weight and fat oxidation during exercise are suggestive for a beneficial effect of moderate physical activity on weight maintenance.

[Purpose] The purpose of this study was to comparatively investigate the correlation among body composition, resting metabolic rate (RMR), and physical activity (PA) between young and middle-aged Korean adults. [Methods] A total of 53 [male n=23, female n=30] subjects were included in this study, among whom 34 subjects were healthy young adults [male n=18, female n=16] and 19 were middle-aged adults [male n=5, female n=14]. The body composition and RMR of all the participants were measured after overnight fasting (≥8 h). The Korean version of the WHO Global Physical Activity Questionnaire (GPAQ) was used to assess physical activity. [Results] Body composition was not significantly different between young adults and middle-aged adults. Whole-body bone mineral density and bone mineral contents (BMC) were significantly lower in middle-aged adults than in young adults. Total blood cholesterol (TC) and blood glucose levels were significantly higher in middle-aged adults (TC; 195.21 ± 43.34, glucose; 103.57 ± 12.61 mg/dL) than in young adults. RMR was significantly lower in middle-aged adults (1619.57 ± 290.28 kcal/day) than in young adults (1894.37 ± 405.00 kcal/day). In middle-aged adults physical activity (PA). PA (METs, min, EE) was inversely correlated with fat mass (FM, kg, and %) and blood triglyceride (TG) level in young adults. In middle-aged adults, PA showed a significant positive correlation with lean body mass (LBM), FM (%), and RMR. Furthermore, PA EE showed significant interrelatedness with BMC among middle-aged adults. [Conclusion] These results demonstrated that high PA levels enable LBM and RMR maintenance in middle- aged adults. Furthermore, in young adults, more PA is required to induce change in body composition.

While exercise training (ET) is an efficient strategy to manage obesity, it is recommended with a dietary plan to maximize the antiobesity functions owing to a compensational increase in energy intake. Capsiate is a notable bioactive compound for managing obesity owing to its capacity to increase energy expenditure. We aimed to examine whether the antiobesity effects of ET can be further enhanced by capsiate intake (CI) and determine its effects on resting energy expenditure and metabolic molecules. Mice were randomly divided into four groups (n = 8 per group) and fed high-fat diet. Mild-intensity treadmill ET was conducted five times/week, capsiate (10 mg/kg) was orally administered daily. After 8 weeks, resting metabolic rate and metabolic molecules were analyzed. ET with CI additively reduced the abdominal fat rate by 18% and solely upregulated beta-3-adrenoceptors in adipose tissue (p = 0.013) but did not affect the metabolic molecules in skeletal muscles. Surprisingly, CI without ET significantly increased the abdominal fat rate (p = 0.001) and reduced energy expenditure by 9%. Therefore, capsiate could be a candidate compound for maximizing the antiobesity effects of ET by upregulating beta-3-adrenoceptors in adipose tissue, but CI without ET may not be beneficial in managing obesity.

Red ginseng (RG) ingestion reportedly affects body weight, food intake, and fat accumulation reduction. It also induces changes in energy metabolism regulation and glycemic control. Previously, 2-week RG ingestion with endurance training was found to enhance fat oxidation during exercise. However, such effects on energy metabolism and the expression of mRNAs related to energy substrate utilization in resting mice (untrained mice) are still unclear. Here, we determined the effect of RG on energy metabolism and substrate utilization in untrained male mice. Twenty-four mice were separated into an RG group that received a daily dosage of 1 g/kg RG for 2 weeks, and a control (CON). Energy expenditure, blood and tissue glycogen levels, and expression of mRNAs related to energy substrate utilization in muscles were measured before and 2 weeks after treatment. Total food intake was significantly lower in the RG than in the CON group (p &lt, 0.05), but final body weights did not differ. Carbohydrate and fat oxidation over 24 h did not change in either group. There were no significant differences in gastrocnemius GLUT4, MCT1, MCT4, FAT/CD36, and CPT1b mRNA levels between groups. Thus, the effects of RG ingested during rest differ from the effects of RG ingestion in combination with endurance exercise, administering RG to untrained mice for 2 weeks did not change body weight and energy metabolism. Therefore, future studies should consider examining the RG ingestion period and dosage for body weight control and improving energy metabolism.

[Purpose] While the anti-obesity effects of exercise and capsiate are well-observed individually, the effect of exercise with capsiate intake has not been system atically explored yet. Therefore, the purpose of this study is to investigate whether the anti-obesity effects of exercise training can be further enhanced by capsi ate intake. [Methods] 8-week-old male mice were divided into 3 groups (n = 8 per group): sedentary group (SED; non-trained), exercise-trained group (EXE) and exercise-trained group with 10 mg/kg of capsiate intake (EXE+CAP). All mice were offered high-fat diet and water ad libitum. The mild-intensity treadmill training was conducted 5 times a week for 8 weeks. After 8 weeks, metabolism during exercise and abdominal fat weight were measured. [Results] Body weight and the rate of total abdominal fat were significantly less in EXE+CAP than in SED but not between EXE and SED. The average of respiratory exchange rate during exercise was significantly much lower in EXE+SED (p = 0.003) compared to the differ ence between EXE and SED (p = 0.025). Likewise, the fat oxidation during exercise was significantly much higher in EXE+SED (p = 0.016) compared to the dif ference between EXE and SED (p = 0.045). Then, the carbohydrate oxidation during exercise was signifi cantly much lower in EXE+SED (p = 0.003) compared to the difference between EXE and SED (p = 0.028). [Conclusion] In conclusion, the anti-obesity functions of exercise training can be further enhanced by capsi ate intake by increasing fat oxidation during exercise. Therefore, we suggest that capsiate could be a can didate supplement which can additively ameliorate obesity when combined with exercise.

The present study aimed to investigate the effects of cold exposure and/or exercise on resting energy metabolism over 24 h and on BAT activity and browning of WAT related gene responses. Forty ICR male mice were divided into four groups: thermoneutrality-untrained (23 ± 1°C in room temperature, n=10), cold-water immersion (24 ± 1°C, n=10), exercise in neutral temperature (34 ± 1°C, n=10), and exercise in cold temperature (24 ± 1°C, n=10). The mice performed swim training (30 min to 60 min, 5 days/week) for 8 weeks. After end of experiment, we confirmed BAT activity and browning of WAT-related gene expression changes in interscapular-BAT and inguinal adipose tissue, and measured resting energy metabolism over 24 h. The results showed that the relative tissue weights of BAT and inguinal fat tissue differed by temperature (p = 0.016, p= 0.001 respectively). The UCP1 mRNA expression in BAT showed a significant effect in the exercised groups (p = 0.038). The sum of the oxygen uptake, only a significant temperature effect (p = 0.040) was observed and the average of the RER showed a significant temperature (p = 0.024) and exercise (p = 0.008) effect. Our data demonstrate that cold exposure and exercise independently induces the gene expression of thermogenic markers and the energy metabolic rate. The relative expression of these markers and the change of the energy metabolism indicators differed across the tissues and experimental treatments. In conclusion, our results suggest that cold exposure and exercise has no synergy effect on thermogenic markers of BAT and beige/brite adipose tissue and energy metabolism over 24h.

[Purpose] Brown adipose tissue (BAT) plays an important role in metabolizing different substances, including androgens. The aim of this study was to determine whether a single bout of aerobic exercise would increase the androgen hormone concentration in mouse BAT and whether its increase was associated with uncoupling protein-1 (UCP-1), protein kinase A (PKA)-related mechanism in BAT. [Methods] Twenty, 9-week-old ICR adult male micewere randomly divided into three groups: Control (n=6, CON), Exercise (n=7, EX), and Exercise + SRD5A1A2 inhibitor (n=7, EXIN). SRD5A1A2 is an enzyme needed when free testosterone is metabolized to dihydrotestosterone (DHT). SRD5A1A2 was administered intraperitoneally in the EXIN group, while the CON and EX groups were treated with the vehicle only. One hour later, exercise was performed at 60–70% V˙O2max for 30minutes. The levels of testosterone and DHT in BAT were determined by ELISA, and UCP-1 mRNA level was examined by RT-PCR. UCP-1 and PKA protein levels were determined by western blotting. [Results] After a single period of exercise, testosterone and DHT concentrations in BAT were significantly higher in EX than those in CON, and lower in EXIN than those in EX. The ratio of phosphorylated PKA to total PKA in BAT was significantly higher in EX than that in CON, and lower in EXIN than that in EX. UCP-1 levels in BAT were not different in the three groups. [Conclusion] Aerobic exercise increased bioactive androgen hormone levels in BAT in association with the increase in phosphorylated PKA levels. In contrast, 30minutes of treadmill exercise did not affect UCP-1 expression.

[Purpose] Dihydrotestosterone (DHT) plays an important role in various processes that utilize energy, including fat and carbohydrate oxidation. The purpose of this study was to determine the effect of inhibiting DHT formation during mid-intensity running exercise on energy expenditure and fat and carbohydrate oxidation in the whole body using a calorimetric chamber. [Methods] Twelve ICR adult male mice, 9 weeks of age, were randomized into two groups: CON (n = 6, no treatment with exercise) and CONIN (n = 6, DHT inhibitor treatment with exercise, SRD5A1A2 is an enzyme involved in the metabolism of free testosterone into DHT). Inhibitor was administered to the CONIN group intraperitoneally, while the CON group was treated with vehicle (corn oil 2 mg/kg). After 3 days of administration of the inhibitor or vehicle, exercise was performed at 60-70% VO2max for 30 min on a treadmill in a calorimetric chamber. The O2 uptake, CO2 production, carbohydrate and fat oxidation, and respiratory exchange ratio (RER) during 30-min exercise were measured using a calorimeter. [Results] During a single bout of exercise, the CONIN group showed a significantly higher area under the curve (AUC) of O2 uptake and CO2 production from 20 min into exercise than the CON group (p < 0.001). The CONIN group showed a significantly higher AUC for carbohydrate oxidation from 20 min into exercise than the CON group (p < 0.001), whereas no difference was found in fat oxidation between groups (p = 0.067). The CONIN group had a significantly higher AUC of RER from 20 min into exercise than the CON group (p < 0.001). [Conclusion] We observed increased energy consumption at the later phase of 30-min moderate-intensity treadmill running when DHT production was inhibited. Furthermore, when DHT production during exercise was inhibited, whole-body fat utilization was inhibited and carbohydrate oxidation was substantially increased at the later phase of exercise compared to in the control group. Therefore, changes in DHT concentration in the body during exercise may be involved in whole-body fat utilization, suggesting that DHT may be an important factor affecting endurance exercise capacity.

[Purpose] Resistance exercise training (RET) and an additional intake of dietary protein supplements may improve muscle mass and muscular function, and reduce inflammatory markers. The types, amount, and timing of dietary protein supplements are important for the synergistic effects of resistance training and dietary protein supplements. We hypothesized that a 25.1 g protein complex supplement taken for 12 weeks, immediately before and after resistance exercise, would enhance fat free mass and isokinetic muscular function in young untrained males. [Methods] Eighteen participants were randomly assigned to a placebo (n=8) or protein complex supplement groups (n=10). The RET was a supervised progressive program, 3 times per week for 12-weeks, and was performed progressing 80% of their one repetition maximum (1-RM). Body composition, blood pressure, plasma inflammatory markers, lipid level and isokinetic muscular function were assessed before and after the study period. [Results] There was a significant interaction effect in C-reactive protein (CRP) (p =0.044) among blood vessel inflammatory markers. The protein complex supplement group had shown more effective improvement at 12 weeks intervention compared to the placebo group in isokinetic muscular function. There was a significant interaction effect in peak torque at 60 degrees/sec leg extension (p =0.044), total work at 240 degrees/sec leg extension (p =0.025), and total work at 240 degrees/sec leg flexion (p =0.011). [Conclusion] Protein complex supplementation during RET appears more effective than RET alone in improving isokinetic muscular function for 12 weeks in untrained young men.

[Purpose] The purpose of this study was to determine whether exercise or/and cold exposure regulate mitochondria biogenesis-related gene expression in soleus and inguinal adipose tissue of mice. [Methods] Forty ICR 5-week old male mice were divided into four groups: thermoneutrality-untrained (23 ± 1 °C in room temperature, n=10), cold-water immersion (24 ± 1 °C, n=10), exercise in neutral temperature (34 ± 1 °C, n=10), and exercise in cold temperature (24 ± 1 °C, n=10). The mice performed swimming exercise (30 min to 60 min, 5 times) for 8 weeks. After 8 weeks, we confirmed mitochondrial biogenesis-related gene expression changes for peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), nuclear respiratory factors 1 (NRF1), and mitochondrial transcription factor A (Tfam) in soleus muscle and inguinal adipose tissue, and the related protein expression in soleus muscle. [Results] In soleus muscle, PGC-1α expression significantly increased in response to cold exposure (p = 0.006) and exercise (p = 0.05). There was also significant interaction between exercise and cold exposure (p = 0.005). Only exercise had a significant effect on NRF1 relative expression (p=0.001). Neither cold exposure nor the interaction showed significant effects (p = 0.1222 and p = 0.875, respectively). Relative Tfam expression did not show any significant effect from exercise. In inguinal adipose tissue, relative PGC-1α expression did not significantly change in any group. NRF1 expression showed a significant change from exercise (p = 0.01) and cold exposure (p = 0.011). There was also a significant interaction between exercise and cold exposure (p = 0.000). Tfam mRNA expression showed a significant effect from exercise (p=0.000) and an interaction between exercise and cold exposure (p=0.001). Only temperature significantly affected PGC-1α protein levels (p=0.045). Neither exercise nor the interaction were significant (p = 0.397 and p = 0.292, respectively). NRF1 protein levels did not show a significant effect in any experimental treatments. Tfam protein levels showed a significant effect in the exercise group (p=0.012), but effects of neither cold exposure nor the interaction were significant (p = 0.085 and p=0.374, respectively). [Conclusion] Exercise and cold exposure promoted increased expression of mitochondrial biogenesis- related genes in soleus muscle. Only cold exposure had a significant effect on PGC-1α protein expression and only exercise had a significant effect on Tfam protein expression. In inguinal adipose tissue, there was interaction between exercise and cold exposure in expression of mitochondrial biogenesis-related genes.

Background Androgen hormone levels are strongly associated with obesity in adult mammals, especially with advanced age. We investigated androgen receptor inhibition on fat metabolism and long-chain fatty acid (LCFA) transport proteins in skeletal muscle during exercise. Methods Male ICR mice were randomly divided into three groups: CON (control), EX (exercise), and EXIN (exercise + androgen receptor inhibition). EX and EXIN groups were trained on a treadmill five times a week. After 4 weeks, the fat metabolism of each group was measured using open-circuit calorimetry during 1 hour of exercise. After the metabolism measurement, the expression levels of LCFA transport proteins (FAT/CD36, CPTI) were analyzed in skeletal muscle. Results Weight gain and final body weight were significantly lower in the EX group than in either the CON or EXIN groups. Conversely, food intake was significantly higher in the EX group than it was in the CON and EXIN groups. The total weight (CON; 2.07 ± 0.6, EX; 1.64 ± 0.2, EXIN; 1.95 ± 0.2) of the abdominal adipose tissue were significantly lower in the EX group than in the CON and EXIN groups (P P P P P P Conclusion Exercise training increases the expression of LCFA transport proteins (FAT/CD36, CPTI). Blocking androgen receptors can decreases the expression of CPTI in the skeletal muscle, which reduces fat metabolism. Thus, reducing sex hormones or suppressing the sensitivity of AR receptors can inhibit energy efficiency and fat metabolism by suppressing CPTI.

[Purpose] The composition of protein supplements, the consumption timing immedi-ately before and after resistance exercise training (RET), and the quantity of protein supplementation may be important factors for the im-provement of muscle mass and function. Although these factors should be considered comprehensively for effective improvement of muscular function in protein supplementation, relatively few studies have focused on this area. Therefore, this study was designed to investigate whether a protein blend supplement before and after resistance exercise for 12 weeks would be effective in increasing muscular function. [Methods] In total, 18 participants were randomly assigned to a placebo (PLA) or protein blend supplement (PRO) group. All subjects followed the same training routine 3 times per week for 12 weeks, taking placebo or protein supplements immediately before and after each exercise session. The protein supplement consisted of 40 g of blend protein, including hydrolyzed whey protein. The RET consisted of lower body (barbell squat, dead lift, seated leg extension, and lying leg curl) and upper body (bench press, barbell rowing, preacher bench biceps curl, and dumbbell shoulder press) exercises. A repetition was defined as three sets of 10-12 times with 80% of one repetition maximum (1RM). [Results] Although the PRO group had a lower protein intake in terms of total food intake than the PLA group, the mean changes in muscle circumference, strength, and exercise volume increased, especially at week 12, compared to the PLA group. [Conclusion] These results suggest that the composition and timing of protein intake are more important than the total amount.

[Purpose] The aim of the present study was to investigate the effects of treatment with silk peptides (SP) on resting energy expenditure over a 24-h period and clarify the molecular mechanism underlying its enhancement of fat utilization in mouse skeletal muscles. [Methods] Sixteen male ICR mice (6-weekold) were divided into two groups and treated with distilled water and SP (CON and SP treatment groups, respectively). SP were dissolved in distilled water and administered to the SP group at 800 mg/kg while the CON group was administered distilled water orally daily for 2 weeks. Resting metabolic rate (RMR) was measured before and after SP ingestion for 2 weeks using an open circuit calorimetry system. After the treatments, we collected blood and skeletal muscle samples from the mice. [Results] Final body weight and body weight gain showed no significant difference in the CON and SP groups. Conversely, food intake was significantly lower in the SP group than it was in the CON group. The comparison of the respiratory exchange rate (RER) at various time points after the 2-week treatment revealed that it was significantly lower in the SP group than it was in the CON group at 9, 15, 16, and 18-22 h (Figure 3 B). The sum of the RER over 24-h was lower in the SP group than it was in the CON group, but the difference was not statistically significant. The protein levels of fatty acid translocase (FAT)/ cluster of differentiation 36 (CD36) were approximately 12% higher in the SP group than they were in the CON group but that of carnitine palmitoyltransferase I (CPTІ) was not significantly different between the two groups. [Conclusion] These results suggest that treatment with SP 800 mg/kg for 2 weeks may promote fat utilization during physical activity, but not the entire day. In addition, SP treatment effectively enhanced FAT/CD36 protein level in skeletal muscle. In future investigations, it would be necessary to elucidate the effects of long-term SP intake on the resting metabolism of both animals and humans.

Ginseng has a long history of use as a tonic for restoration of vigor. One example of ginseng-derived tonic effect is that it can improve physical stamina under conditions of stress. However, the active ingredient and the underlying molecular mechanism responsible for the ergogenic effect are unknown. Recent studies show that ginseng contains a novel ingredient, gintonin, which consists of a unique class of herbal-medicine lysophosphatidic acids (LPAs). Gintonin activates G protein-coupled LPA receptors to produce a transient [Ca(2+)]i signal, which is coupled to diverse intra- and inter-cellular signal transduction pathways that stimulate hormone or neurotransmitter release. However, relatively little is known about how gintonin-mediated cellular modulation is linked to physical endurance. In the present study, systemic administration of gintonin, but not ginsenosides, in fasted mice increased blood glucose concentrations in a dose-dependent manner. Gintonin treatment elevated blood glucose to a maximum level after 30min. This elevation in blood glucose level could be abrogated by the LPA1/3 receptor antagonist, Ki16425, or the β-adrenergic receptor antagonist, propranolol. Furthermore, gintonin-dependent enhanced performance of fasted mice in rotarod test was likewise abrogated by Ki16425. Gintonin also elevated plasma epinephrine and norepinephrine concentrations. The present study shows that gintonin mediates catecholamine release through activation of the LPA receptor and that activation of the β-adrenergic receptor is coupled to liver glycogenolysis, thereby increasing the supply of glucose and enhancing performance in the rotarod test. Thus, gintonin acts via the LPA-catecholamine-glycogenolysis axis, representing a candidate mechanism that can explain how ginseng treatment enhances physical stamina.

We investigated the effects of oral lactate administration on protein synthesis and degradation factors in rats over 2 h after intake. Seven-week-old male Sprague&ndash, Dawley rats were randomly divided into four groups (n = 8/group), their blood plasma levels of lactate, glucose, insulin, and insulin-like growth factor 1 (IGF1) were examined following sacrifice at 0, 30, 60, or 120 min after sodium lactate (2 g/kg) administration. We measured the mRNA expression levels of protein synthesis-related genes (IGF receptor, protein kinase B (Akt), mammalian target of rapamycin (mTOR)) or degradation-related genes (muscle RING-finger protein-1 (MuRF1), atrogin-1) and analyzed the protein expression and phosphorylation (activation) of Akt and mTOR. Post-administration, the plasma lactate concentration increased to 3.2 mmol/L after 60 min. Plasma glucose remained unchanged throughout, while insulin and IGF1 levels decreased after 30 min. The mRNA levels of IGF receptor and mTOR peaked after 60 min, and Akt expression was significantly upregulated from 30 to 120 min. However, MuRF1 and atrogin-1 expression levels were unaffected. Akt protein phosphorylation did not change significantly, whereas mTOR phosphorylation significantly increased after 30 min. Thus, lactate administration increased the mRNA and protein expression of protein-synthesis factors, suggesting that it can potentially promote skeletal muscle synthesis.

Purpose The effect of BCAA (branched chain amino acid) administration on muscle atrophy during growth phases is not well known. We investigated whether BCAA administration can prevent the muscle atrophy induced by hindlimb suspension in growing male rats. Methods Male Wistar rats were assigned to 1 of 2 groups (n = 7/group): hindlimb suspension and hindlimb suspension with oral BCAA administration (600 mg·kg(-1)·day(-1), valine 1: leucine 2: isoleucine 1). After 14 days of hindlimb suspension, the weight and mRNA levels of the soleus muscle were measured. Results BCAA administration prevented a decrease in soleus muscle weight. BCAA administration attenuated atrogin-1 and MuRF1 mRNA expression, which has been reported to play a pivotal role in muscle atrophy. Conclusion BCAA could serve as an effective supplement for the prevention or treatment of muscle atrophy, especially atrophy caused by weightlessness.

PURPOSE: This study was to investigate changes in BCAT and BCKDH genes by Hindlimb-Suspension (HS) and protein intake composition (casein, Whey protein) in rats. METHODS: Following 5-day preliminary feeding, forty-eight male 5 weeks old Sprague Dawley albino rats (110g) divided into 17% protein intake group (24 rats) and 30% protein intake group (24 rats), and each group divided further into Hindlimb-Suspension group (HS; 12 rats) and control group(CON; 12 rats). Eventually, this study was performed with Whey protein intake group (HS; 6 rats, CON; 6 rats) and casein intake group (HS; 6 rats, CON; 6 rats). For analysis purposes, total RNA was extracted from isolated skeletal muscles, and mRNA expression was analyzed using Real Time PCR. Two-way ANOVA was performed to examine the difference in BCATm and BCKDH mRNA expression on protein uptake and myoatrophy. post-hoc test was perform on interaction if any, and significance level was set at p

Background Exercise promotes energy metabolism (e.g., metabolism of glucose and lipids) in skeletal muscles; however, reactive oxygen species are also generated during exercise. Various spices have been reported to have beneficial effects in sports medicine. Here, we investigated the effects of piperine, an active compound in black pepper, to determine its effects on metabolism during acute endurance exercise. Methods ICR mice (n = 18) were divided into three groups: nonexercise (CON), exercise (EX), and exercise with piperine (5 mg/kg) treatment (EP). Mice were subjected to enforced exercise on a treadmill at a speed of 22 m/min for 1 h. To evaluate the inflammatory responses following exercise, fluorescence-activated cell sorting analysis was performed to monitor changes in CD4+ cells within the peripheral blood mononuclear cells (PBMCs) of mice. The expression levels of metabolic pathway components and redox-related factors were evaluated in the soleus muscle by reverse transcription polymerase chain reaction and western blotting. Results There were no changes in the differentiation of immune cells in PBMCs in both the EX and EP groups compared with that in the CON group. Mice in the EX group exhibited a significant increase in the expression of metabolic pathway components and redox signal-related components compared with mice in the CON group. Moreover, mice in the EP group showed greater metabolic (GLUT4, MCT1, FAT/CD36, CPT1, CS) changes than mice in the EX group, and changes in the expression of redox signal components were lower in the EP group than those in the EX group. Conclusion Our findings demonstrate that piperine promoted beneficial metabolism during exercise by regulating carbohydrate/fat metabolism and redox signals. Therefore, piperine may be a candidate supplement for improvement of exercise ability. Electronic supplementary material The online version of this article (doi:10.1186/s12986-017-0194-2) contains supplementary material, which is available to authorized users.

[Purpose] We investigated the effects of endurance training on the expression of long-chain fatty acid transport proteins in the skeletal muscle and whole-body fat oxidation during endurance exercise. [Methods] Seven-week-old male ICR mice (n = 12) were divided into 2 groups, namely, Sed (sedentary; non-trained) and Tr (endurance-trained) groups. The Tr group was adapted to treadmill training at a fixed intensity (15 m/min, 8° slope) for 3 days. Next, the exercise intensity was increased while maintaining the 8° slope. In the last week of training, the exercise intensity was set at 25 m/min for 50 min (about 70–75% maximal oxygen uptake for 4 weeks). After the protocol ended, the mice were sacrificed, and tissues were collected for western blot analysis. [Results] Four weeks of endurance training resulted in a significant increase in the protein levels of FAT/CD36 and CPTІ. The FAT/ CD36 protein level in the Tr group was about 1.3-fold greater than that in the Sed group (p < 0.01). Furthermore, the increased CPTІ indicated higher activity (19% upregulation) in the Tr group compared to the Sed group (p < 0.05). The FAT/CD36 protein level and the estimated whole-body fat oxidation rate during 1-h exercise were found to be significantly correlated (r = 0.765, p < 0.01). [Conclusion] We suggest that the increase in FAT/CD36 protein in skeletal muscle by endurance training might be positively associated with whole-body fat oxidation, which might enhance endurance exercise capacity.

Silk peptides (SP) have been reported to decrease body weight and accumulate fat. We investigated the effects of SP administration by using an open circuit calorimetry system on resting energy expenditure and substrate utilization in resting mice for the duration of 24 h. Seven-week-old male ICR-mice were orally administered SP (800 mg/kg) for 2 wk and were subjected to endurance training. The results indicated that not only was oxygen uptake higher in the SP group than in the CON group (*p

l-Carnitine was recently found to downregulate the ubiquitin proteasome pathway (UPP) and increase insulin-like growth factor 1 concentrations in animal models. However, the effect of l-carnitine administration on disuse muscle atrophy induced by hindlimb suspension has not yet been studied. Thus, we hypothesized that l-carnitine may have a protective effect on muscle atrophy induced by hindlimb suspension via the Akt1/mTOR and/or UPP. Male Wistar rats were assigned to 3 groups: hindlimb suspension group, hindlimb suspension with l-carnitine administration (1250 mg·kg−1·day−1) group, and pair-fed group adjusted hindlimb suspension. l-Carnitine administration for 2 weeks of hindlimb suspension alleviated the decrease in weight and fiber size in the soleus muscle. In addition, l-carnitine suppressed atrogin-1 mRNA expression, which has been reported to play a pivotal role in muscle atrophy. The present study shows that l-carnitine has a protective effect against soleus muscle atrophy caused by hindlimb suspension and decreased E3 ligase messenger RNA expression, suggesting the possibility that l-carnitine protects against muscle atrophy, at least in part, through the inhibition of the UPP. These observations suggest that l-carnitine could serve as an effective supplement in the decrease of muscle atrophy caused by weightlessness in the fields of clinical and rehabilitative research.

Athletes make great efforts to increase their endurance capacity in many ways. Using nutrition supplements for stimulating lipolysis is one such strategy to improve endurance performance. These supplements contain certain ingredients that affect fat metabolism; furthermore, in combination with endurance training, they tend to have additive effects. A large body of scientific evidence shows that nutrition supplements increase fat metabolism; however, the usefulness of lipolytic supplements as ergogenic functional foods remains controversial. The present review will describe the effectiveness of lipolytic supplements in fat metabolism and as an ergogenic aid for increasing endurance exercise capacity. There are a number of lipolytic supplements available on the market, but this review focuses on natural ingredients such as caffeine, green tea extract, L-carnitine, Garcinia cambogia (hydroxycitric acid), capsaicin, ginseng, taurine, silk peptides and octacosanol, all of which have shown scientific evidence of enhancing fat metabolism associated with improving endurance performance. We excluded some other supplements owing to lack of data on fat metabolism or endurance capacity. Based on the data in this review, we suggest that a caffeine and green tea extract improves endurance performance and enhances fat oxidation. Regarding other supplements, the data on their practical implications needs to be gathered, especially for athletes.

This study investigated the effect of a long-term high-fat diet on energy metabolic substrate utilization in resting rats in order to revalue source fat energy efficiency during a high-fat diet and its effect on energy expenditure and body fat accumulation. Sprague-Dawley male rats at 4 weeks of age were bought from Orient Bio Con. The rats were divided into a control (CON) group and a high-fat diet (HF) group. Rats ate a high-fat diet (w/w 40%, kcal/kcal 64.9%) ad libitum for 5 weeks. Food intake and body weight were measured every day at 09:00 throughout the experimental period. Energy expenditure was measured using an animal energy metabolism chamber after 4 weeks. The final body weight did not change between the CON and HF groups, but caloric intake was significantly higher in the HF group than in the CON group (p

The aim of this study was to determine whether there was an association between body fat distribution, blood lipid profiles, and beta 3-adrenergic receptor gene polymorphism in Korean middle-aged women. Subjects were grouped according to BMI as obese (or = 5 BMI, n = 95) or non-obese (BMI25, n = 93). The Trp64Arg mutation of the beta 3-adrenergic receptor gene was detected by PCR-RFLP. Skinfold thickness, body circumference, intra-abdominal fat area by CT, and blood lipid profiles were also measured. Data were compared using ANOVA, Bonferroni t-test, and Chi-square. Significance for statistical analyses were set at p0.05. In the obese group, 63.16% were Trp64Trp homozygotes and 36.84% were Trp64Arg heterozygotes, compared to 80.65% who were Trp64Trp homozygotes and 19.35% who were Trp64Arg heterozygotes in the non-obese group. These results indicated a significant (chi-square = 4.943, p0.05) difference between the two groups. Frequency of the Arg64 allele in the obese group (16.84%) showed a significant (chi-square = 4.185, p0.05) difference as compared to the non-obese group (9.68%). Skinfold thickness and body circumference of the Trp64Arg heterozygote group showed a consistent increase as compared to the Trp64Trp homozygote group. Visceral fat area and VSR of Trp64Arg heterozygote group showed a higher tendency than Trp64Trp homozygotes in the obese group, but these differences were not statistically significant. In conclusion, the Trp64Arg polymorphism of the beta 3-adrenergic receptor gene is associated with obesity in middle-aged Korean women, but it is difficult to suggest the prominent association of the Trp64Arg polymorphism of the beta 3-adrenergic receptor gene with prevalence of abdominal obesity or dyslipidemia in Korean middle-aged women.

We have been interested in the ergogenic aid effects of food components and supplements for enhancing endurance exercise performance. For this purpose, acute or chronic (-)-hydroxycitrate (HCA) ingestion might be effective because it promotes utilization of fatty acid as an energy source. HCA is a competitive inhibitor of the enzyme ATP: citrate lyase, thereby increasing inhibition of lipogenesis in the body. Many researchers have reported that less body fat accumulation and sustained satiety cause less food intake. After focusing on exercise performance with HCA ingestion, we came up with different results that show positive effects or not. However, our previously reported data showed increased use of fatty acids during moderate intensity exercise. For future research, HCA and co-ingestion of other supplements, such as carnitine or caffeine, might have greater effect on glycogen-sparing than HCA alone.

(-)-Hydroxycitric acid (HCA) is a competitive inhibitor of the enzyme ATPcitrate-lyase, which inhibits lipogenesis in the body. Moreover, HCA increases endurance exercise performance in trained mice and athletes. However, had not been investigated in untrained animals and humans. Therefore, we investigated the effects of short-term HCA ingestion on endurance exercise performance and fat metabolism in untrained women. In two experiments designed as a double-blind crossover test, six subjects ingested 250 mg of HCA or placebo (same amount of dextrin) via capsule for 5 d and then participated in cycle ergometer exercise. They cycled at 40% VO2max for 1 h and then the exercise intensity was increased to 60% VO2max until exhaustion on day 5 of each experiment. HCA tended to decrease the respiratory exchange ratio (RER) and carbohydrate oxidation during 1 h of exercise. In addition, exercise time to exhaustion was significantly enhanced (p

(-)-Hydroxycitrate (HCA) is known to inhibit increasing malonyl CoA concentration during endurance exercise. Furthermore, a short-term administration of HCA enhances endurance exercise performance in mice. Therefore we investigated the short-term administration of HCA on the exercise performance of athletes. Subjects were administered 250 mg of HCA or placebo as a control (CON) for 5 d, after each time performing cycle ergometer exercise at 60% VO2max for 60 min followed by 80% VO2max until exhaustion. Blood was collected and expired gas samples analyzed at rest and every 15 min. The respiratory exchange ratio was significantly lower in the HCA trial than in the CON trial (p < 0.05). Fat oxidation was significantly increased by short-term administration of HCA, and carbohydrate oxidation was significantly decreased (p < 0.05) during exercise, presumably resulting in increasing the cycle ergometer exercise time to exhaustion after 1 h of 60% VO2max exercise (p < 0.05). These results suggest that a short-term administration of HCA enhances endurance performance with increasing fat oxidation, which spares glycogen utilization during moderate intensity exercise in athletes.

Caffeine is one of the famous ergogenic aids in the athletic field. Caffeine has been known to stimulate lipolysis that spares stored glycogen utilization during moderate intensity exercise. Therefore, we investigated the effects of caffeine ingestion on exercise performance in rats and athletes. Rats were administered the caffeine (6 mg/kg) 1 h prior to the exercise then were run on a treadmill at a speed of 20 m/min. They were decapitated at 0 min, 30 min, 60 min of exercise, and exhausted time point. Human subjects ingested the caffeine (5 mg/kg) 1 h prior to the exercise. They exercised on a cycle ergometer at 60% of their VO2max for 45 min, and then the exercise intensity was increased to 80% of their VO2max until exhaustion. Blood and breathing gas samples were collected and calculated every 10 min during exercise. Respiratory exchange ratio of the caffeine trial was significantly lower than that of the placebo trial in the athletes' study (p

The purpose of this study was to examine whether caffeine (CAF), carnitine (CAR), or CAF+CAR mixture administration affects exercise endurance time via carnitine metabolism. Water (CON), CAF, CAR, or CAF+CAR mixture was administered to five male rugby athletes participating in this study by a randomized double-blind fashion who were made to ride a cycle ergometer for exercise. The CAF effect on exercise endurance time was small, but the CAR trial significantly increased the exercise endurance time compared with CON trial; a further CAF+CAR mixture trial had greater effects on the exercise endurance time than those of a CON, CAF, or CAR trial. A CAR or CAF+CAR mixed trial increased urinary nonesterified carnitine (NEC) and total carnitine (TCAR), but no changes were observed in acid-soluble acylcarnitine (ASAC) and acid-insoluble acylcarnitine (AIAC) excretion. A CAR or CAF+CAR mixed trial resulted in higher levels of plasma NEC, ASAC, and TCAR fractions than the CON and CAF trials did on exhaustion time. Total cholesterol, triglyceride, and free fatty acid in blood were significantly increased at exhaustion time, but they were not affected in the CAF or the CAR trial. These results suggest that carnitine ingestion could promote fat oxidation, resulting in higher endurance performance in athletes, and especially these ergogenic effects of carnitine coingested with caffeine may be greater than those of carnitine alone.

(-)-Hydroxycitrate (HCA) is an active ingredient that is extracted from the rind of the Indian fruit, Garcinia cambogia, which is available as an herbal supplement and is used to lose weight. In this study, the acute and chronic effects of HCA on energy metabolism were examined in male Std ddY mice. Mice were placed into metabolic chambers and administered 10 mg HCA or water (control) orally. Serum free fatty acid levels were significantly higher 100 min after administration in the HCA group, but the respiratory exchange ratio was not different from that in the control group. The concentration of glycogen in the gastrocnemius muscle was higher in the HCA group 16 h after administration, and in a separate study, the maximum swimming time until fatigue was slightly longer (P: = 0. 21) than that in the control group on d 1. The difference was significant on d 3 after 3 d of HCA or water administration. Other mice were administered 10 mg HCA or water orally twice a day for 25 d. On d 26, they were placed into metabolic chambers after administration and allowed to rest for 1 h, followed by 1 h of running at 15 m/min. Respiratory gas was monitored. The respiratory exchange ratio was significantly lower in the HCA group during both resting and exercising conditions. These results suggest that chronic administration of HCA promotes lipid oxidation and spares carbohydrate utilization in mice at rest and during running.

This study was undertaken to determine whether capsaicin may influence abdominal fat deposition and circulating free-fatty acids in exercise-trained rats. In addition, the contribution of beta-adrenergic stimulation to capsaicin-induced changes in serum free-fatty acids was examined. All rats (n=144) were submitted to a treadmill exercise protocol for 14 days. During the first seven days, they were all fed ad libitum with a diet supplemented with capsaicin. Two thirds of rats maintained this diet during the last seven days (capsaicin-diet group) whereas the other rats were pair fed without capsaicin intake (control-diet group). At the end of the protocol, the acute effect of beta-adrenergic blockade (propranolol) on serum free fatty acid concentrations was tested in half of the capsaicin-diet group (propranolol-capsaicin-diet group). A placebo was injected to all other rats, i. e., the other half of rats in the capsaicin-diet group (placebo-capsaicin-diet group) and those in the control-diet group. Epididymal adipose tissue weight was significantly lower in the placebo-capsaicin-diet and propranorol-capsaicin-diet groups than in the control-diet group (p

The effects of dietary hot red pepper on energy metabolism at rest and during exercise were examined in long distance male runners 18-23 yr of age. A standardized meal was given on the evening prior to the experiment. The subjects had a meal (2720 kJ) with or without 10 g of hot red pepper for breakfast. During rest (2.5 h after meal) and exercise (pedaling for 1 h at 150 W, about 60% VO2max, using cycling ergometry), expired gasses and venous blood were collected. The meal with hot red pepper significantly elevated respiratory quotient and blood lactate levels at rest and during exercise. Oxygen consumption at rest was slightly but nonsignificantly higher in the hot red pepper meal at 30 min after the meal. Plasma epinephrine and norepinephrine levels were significantly higher in those who had only hot red pepper at 30 min after the meal. These results suggest that hot red pepper ingestion stimulates carbohydrate oxidation at rest and during exercise.

We examined the effects of (-)-Hydroxycitrate (HCA) ingestion on fat oxidation during moderate intensity exercise in untrained men. Six subjects ingested 500 mg of HCA or a placebo for 5 days and did endurance exercise. Blood FFA concentrations were significantly increased and respiratory exchange ratio (RER) decreased by HCA ingestion. These results suggested short-term HCA ingestion increases fat oxidation in untrained men.

We investigated the effects of dietary red pepper on the energy metabolism in male subjects. In the first experiment, after having a standardized dinner on the previous evening, the subjects consumed a breakfast (650 kcal) either with or without 10 g of red pepper. For 150 min after the meal, they took a rest and their expired gas was collected. During the initial 30 min after the meal, the energy expenditure tended to be higher in the red-pepper diet period than in the control diet period. For the remaining 120 min, no difference in the energy expenditure was found between the red-pepper diet period and the control diet period. However the carbohydrate oxidation was significantly higher in the red-pepper diet period than in the control diet period while the lipid oxidation was lower in the red-pepper diet period than in the control diet period for 150 min after the meal. In the second experiment, the subjects consumed a breakfast with 10 g of red pepper after an oral administration of propranolol or a placebo. The propranolol abolished the increase in energy expenditure during the initial 30 min due to the meal containing red pepper. For the remaining 120 min, no difference in energy expenditure was found between the propranolol period and the placebo period. These results suggest than an increase in the energy expenditure after the meal containing red pepper appeared only immediately after the meal ingestion and a red-pepper diet increases the carbohydrate oxidation without increasing total energy expenditure for 150 min after the meal. And an increase in the energy expenditure immediately after the meal containing red pepper is considered to be caused by beta-adrenergic stimulation.

On the hypothesis that rat hepatic microsomal type I iodothyronine 5'-monodeiodinase (MDI) would be identical to hepatic protein disulfide isomerase (PDI) (Boado et al. Biochem. Biophys. Res. Commun. 155 1297-1304 (1988)), we examined the responses of these enzyme activities to dietary fat and thyroid status in rats. The hepatic MDI activity was higher in rats fed high fat diet than in rats fed low fat diet, but the hepatic PDI activity showed the reverse responses to the diets. Propylthiouracil administration (hypothyroidism) lowered the MDI activity, but elevated the PDI activity. Thyroxine administration (hyperthyroidism) elevated the MDI activity but had no effect on the PDI activity. These results indicate that the two enzyme activities are regulated by different mechanisms in vivo, suggesting that MDI and PDI are not identical enzymes.