著者

Ayumi Fukazawa Takuya Karasawa Yuma Yokota Saki Kondo Toshiaki Aoyama Shin Terada

出版者

Japan Oil Chemists' Society

雑誌

Journal of Oleo Science (ISSN:13458957)

巻号頁・発行日

vol.70, no.7, pp.989-993, 2021 (Released:2021-07-01)

参考文献数

19

被引用文献数

2

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We previously reported that consuming a ketogenic diet containing medium-chain triacylglycerols (MCTs) might be a valuable dietary strategy for endurance athletes. However, the long-term safety of the diet has not been established, and there is a concern that a higher intake of MCTs increases the liver triacylglycerol content. In this study, we found that consuming an MCT-containing ketogenic diet for 24 weeks decreased, rather than increased, the liver triacylglycerol concentration and did not aggravate safety-related blood biomarkers in male Wistar rats. Our results may therefore suggest that the long-term intake of a ketogenic diet containing MCTs may have no deleterious effects on physiological functions.

著者

Yumiko Takahashi Yutaka Matsunaga Yuki Tamura Eiki Urushibata Shin Terada Hideo Hatta

出版者

The Japanese Society of Physical Fitness and Sports Medicine

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.3, no.5, pp.531-537, 2014-11-25 (Released:2014-12-05)

参考文献数

26

被引用文献数

4 6

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Previous studies suggested that taurine (2-aminoethanesulfonic acid) administration enhances glucose uptake, one of the rate-limiting factors for glycogen synthesis. In this study, we investigated the effects of post-exercise taurine administration on glycogen repletion in skeletal muscle in ICR mice. In experiment 1, we orally administered either taurine (0.5 mg/g body weight) solution or physiological saline immediately after treadmill running at 25 m/min for 90 min. The serum free fatty acid (FFA) concentration at 60 min after the exercise was significantly higher in the taurine-treated group compared with the control group (p < 0.05). At 120 min after the exercise, the tibialis anterior muscle glycogen concentration in the taurine-treated group was significantly higher than that in the control group (p < 0.05). In experiment 2, we orally administered either glucose (1 mg/g body weight) solution or glucose solution containing taurine immediately after and at 60 min after the exercise. The area under the curve (AUC) for blood glucose concentration from 0 to 60 min after the exercise was significantly smaller in the taurine-treated group compared with the control group (p < 0.01). Our results show that post-exercise taurine administration enhances glycogen repletion in skeletal muscle. Higher skeletal muscle glycogen concentration by taurine administration may be partly due to the acceleration of glucose uptake. In addition, as the elevation of blood FFA level leads to an increase in fat oxidation, it is possible that a higher serum FFA concentration by taurine treatment is related to the sparing of carbohydrate for glycogen repletion.

著者

Yumiko TAKAHASHI Yutaka MATSUNAGA Yuki TAMURA Shin TERADA Hideo HATTA

出版者

Center for Academic Publications Japan

雑誌

Journal of Nutritional Science and Vitaminology (ISSN:03014800)

巻号頁・発行日

vol.63, no.5, pp.323-330, 2017 (Released:2017-12-08)

参考文献数

47

被引用文献数

4

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Previous studies have shown that the short-term intake of a high-fat diet (HFD) impairs glucose metabolism. In this study, we investigated the influences of pre-exercise HFD intake for 3 d on post-exercise glycogen repletion in skeletal muscle in ICR mice. Mice received either an HFD (57% kcal from fat, 23% kcal from carbohydrate; HFD group) or standard laboratory chow (13% kcal from fat, 60% kcal from carbohydrate; Con group) for 3 d before exercise. Mice performed treadmill running at 25 m/min for 60 min and were orally administered a glucose (2 mg/g body weight) solution immediately after and at 60 min after exercise. A negative main effect of pre-exercise HFD intake was observed for skeletal muscle glycogen concentration from the pre-exercise phase to 120 min of post-exercise recovery (p<0.01). Blood glucose concentration in the HFD group was significantly higher than in the Con group at 120 min after exercise (p<0.01). No significant difference was observed in plasma insulin concentration. There were no significant between-group differences in the phosphorylation state of Akt Thr308, AMPK Thr172, AS160 Thr642, or glycogen synthase Ser641 or in glucose transporter 4 protein levels during post-exercise recovery. Our results suggest that the intake of a pre-exercise HFD for 3 d affects post-exercise glycogen repletion in skeletal muscle without impairing the insulin signaling cascade.

著者

Saki KONDO Takuya KARASAWA Ayumi FUKAZAWA Atsuko KOIKE Momoko TSUTSUI Shin TERADA

出版者

Center for Academic Publications Japan

雑誌

Journal of Nutritional Science and Vitaminology (ISSN:03014800)

巻号頁・発行日

vol.68, no.2, pp.97-103, 2022-04-30 (Released:2022-04-30)

参考文献数

28

被引用文献数

3

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We previously reported that the combination of a very high-carbohydrate diet and endurance training increased glucose transporter 4 and glycogen concentration in skeletal muscle. However, it remains unclear whether they also affect the digestive and absorptive capacity in the pancreas and small intestine, which are suggested to be rate-limiting steps in the delivery of exogenous carbohydrates to skeletal muscle and muscle glycogen synthesis. Thus, we aimed to evaluate the effects of a very high-carbohydrate diet and endurance training on pancreatic amylase activity and intestinal glucose transporters in rats and to examine the relationship between these adaptations and their influence on muscle glycogen concentration. Male Sprague–Dawley rats (n=29) were fed a high-carbohydrate diet (59% carbohydrate) or a very high-carbohydrate diet (76% carbohydrate) for 4 wk. Half of the rats in each dietary group were subjected to 6-h swimming exercise training (two 3-h sessions separated by 45 min of rest) for 4 wk. Although there was no significant effect of diet or endurance training on sodium-dependent glucose transporter 1 and glucose transporter 2 contents in the intestine, the rats fed a very high-carbohydrate diet in combination with endurance training had substantially higher pancreatic amylase activity and muscle glycogen concentration. Furthermore, there was a positive correlation between pancreatic amylase activity and muscle glycogen concentration (r=0.599, p=0.001). In conclusion, intake of a very high-carbohydrate diet and endurance training synergistically elevated carbohydrate digestive capacity, which partially accounted for the higher muscle glycogen accumulation.

著者

Haruki Momma Susumu S. Sawada Robert A. Sloan Yuko Gando Ryoko Kawakami Shin Terada Motohiko Miyachi Chihiro Kinugawa Takashi Okamoto Koji Tsukamoto Cong Huang Ryoichi Nagatomi Steven N. Blair

出版者

Japan Epidemiological Association

雑誌

Journal of Epidemiology (ISSN:09175040)

巻号頁・発行日

pp.JE20160199, (Released:2017-11-25)

参考文献数

29

被引用文献数

6

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Background: The “Physical Activity Reference for Health Promotion 2013” provides “fit” reference values for cardiorespiratory fitness (CRF) for good health. The importance of achieving a fit CRF level for several years on the subsequent prevention of type 2 diabetes mellitus (T2DM) remains to be clarified.

著者

Yudai Nonaka Tetsuo Takagi Makoto Inai Shuhei Nishimura Shogo Urashima Kazumitsu Honda Toshiaki Aoyama Shin Terada

出版者

公益社団法人 日本油化学会

雑誌

Journal of Oleo Science (ISSN:13458957)

巻号頁・発行日

pp.ess16069, (Released:2016-07-15)

被引用文献数

34

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Coconut oil has recently attracted considerable attention as a potential Alzheimer’s disease therapy because it contains large amounts of medium-chain fatty acids (MCFAs) and its consumption is thought to stimulate hepatic ketogenesis, supplying an alternative energy source for brains with impaired glucose metabolism. In this study, we first reevaluated the responses of plasma ketone bodies to oral administration of coconut oil to rats. We found that the coconut oil-induced increase in plasma ketone body concentration was negligible and did not significantly differ from that observed after high-oleic sunflower oil administration. In contrast, the administration of coconut oil substantially increased the plasma free fatty acid concentration and lauric acid content, which is the major MCFA in coconut oil. Next, to elucidate whether lauric acid can activate ketogenesis in astrocytes with the capacity to generate ketone bodies from fatty acids, we treated the KT-5 astrocyte cell line with 50 and 100 μM lauric acid for 4 h. The lauric acid treatments increased the total ketone body concentration in the cell culture supernatant to a greater extent than oleic acid, suggesting that lauric acid can directly and potently activate ketogenesis in KT-5 astrocytes. These results suggest that coconut oil intake may improve brain health by directly activating ketogenesis in astrocytes and thereby by providing fuel to neighboring neurons.

著者

Yuma Yokota Ayumi Fukazawa Yudai Nonaka Takuya Karasawa Michiyo Kimura Shin Terada

出版者

Japan Oil Chemists' Society

雑誌

Journal of Oleo Science (ISSN:13458957)

巻号頁・発行日

vol.72, no.9, pp.849-858, 2023 (Released:2023-08-31)

参考文献数

35

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Dietary intake of medium-chain triacylglycerols (MCTs) is known to alleviate obesity. MCTs have also been suggested to beneficially influence protein metabolism. This study evaluated the effects of dietary intake of MCTs on energy restriction-induced weight control and loss of skeletal muscle. Rats were divided into the following groups: 1) AL-LCT group that received the AIN-93G-based control diet containing long-chain triacylglycerols (LCTs) ad libitum, 2) ER-LCT group fed the control diet with 30% energy restriction, and 3) ER-MCT group fed a diet containing MCTs with 30% energy restriction. After the 4-wk dietary treatment, both energy-restricted groups had significantly lower body weight than the AL-LCT group and rats in the ER-MCT group were significantly lighter than those in the ER-LCT group. In contrast, the extent of energy restriction-induced loss of skeletal muscle was not significantly different between the two energy-restricted groups, resulting in an increase in muscle mass relative to body weight in the ER-MCT group. Despite maintaining the lower body weight, dietary intake of MCTs did not further influence signaling pathways involved in protein synthesis or breakdown. These results suggest that intake of MCTs could be a valuable dietary intervention to maintain a lower body weight and increase relative muscle mass without negative effects on skeletal muscle protein metabolism.

著者

Takuya Karasawa Saki Kondo Ayumi Fukazawa Atsuko Koike Momoko Tsutsui Shin Terada

出版者

Japan Oil Chemists' Society

雑誌

Journal of Oleo Science (ISSN:13458957)

巻号頁・発行日

pp.ess20248, (Released:2021-01-15)

被引用文献数

5

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Endurance exercise training enhances muscle fat oxidation while concomitantly reducing carbohydrate (glycogen) utilization during exercise, thereby delaying the onset of fatigue. This study examined the effects of dietary fat restriction on endurance training-induced metabolic adaptations in rat skeletal muscle. Male Sprague-Dawley rats were placed on either a control diet (CON: 19.2% protein, 21.6% fat, and 59.2% carbohydrate as a percentage of total energy) or a fat-restricted diet (FR: 21.5% protein, 2.4% fat, and 76.1% carbohydrate as a percentage of total energy) for 4 wks. Half the rats in each dietary group performed daily 6-h swimming exercise (two 3-h sessions separated by 45 min of rest) on 5 days each wk. Endurance training significantly increased the expression of β-hydroxyacyl CoA dehydrogenase (βHAD), a key enzyme of fat oxidation, and pyruvate dehydrogenase kinase 4 (PDK4), an inhibitory regulator of glycolytic flux, in the skeletal muscle of rats fed the CON diet. However, such endurance training-induced increases in muscle βHAD and PDK4 were partially suppressed by the FR diet, suggesting that a FR diet may diminish the endurance training-induced enhancement of fat oxidation and reduction in glycogen utilization during exercise. We then assessed the muscle glycogen utilization rate during an acute bout of swimming exercise in the trained rats fed either the CON or the FR diet and consequently found that rats fed the FR diet had a significantly higher muscle glycogen utilization rate during exercise compared with rats fed the CON diet. In conclusion, dietary fat restriction may attenuate the endurance training-induced metabolic adaptations in skeletal muscle.

著者

Shin Terada Seiji Sekine Toshiaki Aoyama

出版者

Japan Oil Chemists' Society

雑誌

Journal of Oleo Science (ISSN:13458957)

巻号頁・発行日

vol.64, no.6, pp.683-688, 2015 (Released:2015-06-01)

参考文献数

20

被引用文献数

3 15

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We examined the effects of the dietary intake of medium- and long-chain triacylglycerol (MLCT) on hyperglycemia in diabetic ob/ob mice. Six-week-old male ob/ob mice were fed a diet containing longchain triacylglycerol (LCT) or MLCT for 3 wks. During the dietary treatment, we determined the plasma glucose and insulin concentrations in the fed state once a week. Whereas the body weights did not differ between the two groups, the total intra-abdominal fat mass was significantly higher in the MLCT group compared to the LCT group. The plasma glucose levels in the freely fed state gradually increased during the 3-wk dietary treatment in the LCT but not MLCT group, although the daily food intake did not differ between the two groups. In the fed state, the MLCT group’s plasma glucose was significantly lower and their insulin concentrations were significantly higher than those observed in the LCT group (p<0.01). Plasma glucose concentrations at the end of dietary treatment (3rd wk) were negatively correlated with plasma insulin concentrations (p<0.05) and tended to be inversely related to total intra-abdominal fat mass (p=0.08). These results suggest that the dietary intake of MLCT may delay the progression of hyperglycemia in ob/ob mice, possibly through the stimulation of glucose uptake in intra-abdominal fat tissue caused by enhanced insulin secretion.

著者

Kazuhiko Higashida Izumi Tabata Mitsuru Higuchi Shin Terada

出版者

一般社団法人日本体力医学会

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.2, no.3, pp.355-360, 2013-08-25 (Released:2013-09-08)

参考文献数

42

被引用文献数

1 1

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Skeletal muscle is the primary site of glucose uptake in humans. Glucose transport activity, which is the rate-limiting step in muscle glucose metabolism, is linearly related to the content of the GLUT-4 isoform of the glucose transporter. Therefore, the level of GLUT-4 in skeletal muscle may be an important determinant of whole-body glucose disposal. It has been well documented that long-term, low- to moderate-intensity endurance exercise training induces an increase in muscle GLUT-4 content. However, emerging evidence suggests that an adaptive increase in GLUT-4 occurs even after a single acute bout of exercise or high-intensity intermittent exercise training. Recent findings also indicate that nutritional status affects GLUT-4 expression in skeletal muscle. This review provides an overview of the effects of exercise and nutritional status on GLUT-4 content in skeletal muscle, and summarizes recent progress in elucidating the molecular regulation of muscle GLUT-4 gene expression by exercise and nutritional stimuli.