運動後同時攝取碳水化合物及羥基檸檬酸對人體骨骼肌第四型葡萄糖轉運子、脂肪酸轉位酶及肌肉肝醣再合成的影響

Effects of coingestion of carbohydrate and HCA as post-exercise supplementation on GLUT4, FAT/CD36 and glycogen resynthesis in human skeletal muscles

朱映婕(Ying-chieh Chu)

指導教授 ： 張照夫 ； 程一雄

中臺科技大學/健康科學院/醫學生物科技研究所/碩士(2009年)

摘要

多數運動員會使用營養增補劑，如蛋白質、肌酸 (creatine) 或咖啡因 (caffeine) 等，提升運動表現。 羥基檸檬酸 ((-)-hydroxycitric acid, HCA) 是由藤黃果果皮萃取的植物性增補劑，能有效抑制 ATP -檸檬酸裂解酶，增加脂肪氧化，減少脂肪合成及增加肌肉肝醣。 羥基檸檬酸能促進肝醣合成進而提升運動表現之作用，少有文獻可稽，本研究之目的在於探討運動後攝取同時攝取碳水化合物膳食及 HCA 萃取物對肌肉肝醣再合成的影響，以第四型葡萄糖轉運子 (glucose transporter type 4, GLUT4) 及脂肪酸轉位酶 (fatty acid translocase/cluster of differentiation 36, FAT/CD36) 的變化為主要評估因素。 八名健康男性 (年齡22.00 ± 0.27歲) 自願參加本研究的2次實驗；實驗採交叉設計，2次實驗相隔7天。 受試者於每次實驗進行70% VO2 peak 腳踏車運動60分鐘。 運動後給予 HCA (500 mg/day) 及碳水化合物膳食 (2 g/kg) (HCA組)，對照組僅給予碳水化合物膳食。 運動後採集肌肉及血液檢體，肌肉檢體採集時間為運動後第0及第3小時；血液檢體採集時間為運動後每30分採集1次，至3小時為止。 肌肉檢體分析項目為肌肉肝醣濃度、GLUT4、FAT/CD36 mRNA 和蛋白質。 血液檢體分析項目為血糖、胰島素及游離脂肪酸濃度。 研究結果顯示: 運動後胰島素濃度，HCA組 (108.0 mg/dL) 比對照組 (118.5 mg/dL) 顯著較低 (p＜0.05)，但血糖濃度，HCA 組 (94.6 mg/dL) 與對照組 (97.8 mg/dL) 無顯著差異 (p＞0.05)。 運動後3小時 FAT/CD36 mRNA 含量之表現，HCA 組為 ( 1.68 AU)，對照組為 (1.07 AU)，極顯著增加57.7% (p＜0.01)，但是 FAT/CD36 蛋白質濃度，HCA 組為 (58.0 AU)，對照組為 (55.8 AU)，二組相比無明顯差異；GLUT4 mRNA 含量之表現，HCA 組 (4.8 AU) 減少21.8%，對照組 (2.7 AU) 減少31.6%，與運動後0小時相比二組皆有顯著差異 (p＜0.05)； GLUT4 蛋白質濃度，HCA 組 (42.2 AU) 減少21.7%，對照組 (56.5 AU) 無顯著差異 (p>0.05)。 值得注意的是，運動後恢復期肌肉肝醣合成量，HCA 組增加了27 μmol/g，對照組增加了12.5 μmol/g，與對照組相比明顯增加22.1% (p<0.05)。 綜合上述實驗數據推測，運動恢復期間立即同時給予碳水化合物膳食和 HCA 可以增加脂肪酸氧化，節省碳水化合物的消耗，有利於人體骨骼肌肝醣再合成。 總而言之，運動後立即同時攝取碳水化合物膳食與 HCA 可增加肌肉肝醣合成量，有利運動員迅速恢復體力。

關鍵字

羥基檸檬酸 ； 脂肪酸轉位酶 ； 肌肉肝醣 ； 第四型葡萄糖轉運子

並列摘要

Most athletes used ergogenic supplements including protein, creatine and caffeine to enhance performance. According to human studies, performance was enhanced through the increased level of skeletal muscle glycogen. (-)-Hydroxycitric acid (HCA) is an herbal supplement which is a potent competitive inhibitor of ATP-citrate lyase. HCA has been used as anti-obesity treatment via decreased fat resynthesis and increased fat oxidation. However, little is known regarding whether coingestion of HCA with carbohydrate meal following exercise causes the increased level of skeletal muscle glycogen via increasing in fat oxidative capacity and sparing in carbohydrate oxidation in human skeletal muscle. The purpose of this study was to investigate coingestion of HCA with carbohydrate meal following exercise, and to verify the gene expression of glucose transporter type 4 (GLUT4) and fatty acid translocase/cluster of differentiation 36 (FAT/CD36). Eight healthy active male volunteers (22.00 ± 0.27 years of age) were the subjects for two experiments carried out at an interval of 7 days, designed in a two-way crossover manner. Subjects were subjected to a 60-min cycling exercise at 70% VO2peak. After exercise, subjects consumed either a high carbohydrate meal (2g/kg body weight) (control group) or coingestion of HCA (500 mg/day) with carbohydrate supplementation (HCA group). Samples were taken for analyses during the 3-h recovery period: muscle samples taken at 0 and 3 h, postprandial blood samples every 30-min. The analyses performed included 1) concentrations of GLUT4
and FAT/CD36 mRNA and protein and glycogen in the muscle samples, 2) concentrations of glucose, insulin and free fatty acid in the blood samples. The results indicated that, in the 3-h recovery period, the HCA group exhibited a significantly lower insulin secretion level (p＜0.05), but no differences were observed for the concentrations of glucose (p＞0.05) as compared with those in the control group. In addition, it was found that 1) the level of glycogen synthesis in HCA group was 22.1% higher than that in the control group (p＜0.05), 2) FAT/CD36 mRNA in the HCA group increased by 57.7%, but no differences were found for the level of FAT/CD36 protein, 3) the level of GLUT4 mRNA decreased significantly in HCA and control groups (decreased by 21.8% and 31.6%, respectively), and 4) the GLUT4 protein decreased by 21.7％ in the HCA group, but not in the control group. These results suggest that coingestion of HCA with post-exercise carbohydrate supplementation enhances fatty acid oxidation, thus reduces carbohydrate catabolism, which in turn favors glycogen re-synthesis. In conclusion, coingestion of HCA with carbohydrate supplementation during post-exercise recovery can be an effective way to enhance muscle glycogen re-synthesis.

並列關鍵字

GLUT4 ； FAT/CD36 ； muscle glycogen ； (-)-hydroxycitric acid

參考文獻

Aberg W, Thorne A, Olivecrona T, Nordenstrom J. 2006. Fat oxidation and plasma removal capacity of an intravenous fat emulsion in elderly and young men. Nutrition 22:738-743.

Arkinstall MJ, Tunstall RJ, Cameron-Smith D, Hawley JA. 2004. Regulation of metabolic genes in human skeletal muscle by short-term exercise and diet manipulation. Am J Physiol Endocrinol Metab 287: 25-31.

Aulin KP, Söderlund K, Hultman E. 2000. Muscle glycogen resynthesis rate in humans after supplementation of drinks containing carbohydrates with low and high molecular masses. J Appl Physiol 81: 346-351.

Baar K, Blough E, Dineen B, Esser K. 1999. Transcriptional regulation in response to exercise. Exerc Sport Sci Rev 27: 333-79.

Baillie AG, Coburn CT, Abumrad NA. 1996. Reversible binding of long-chain fatty acids to purified FAT, the adipose CD36 homolog. J Membr Biol 153: 75–81.