补充大剂量肌酸抑制运动训练大鼠内源性肌酸的合成  

Endogenous Biosynthesis of Creatine Could be Depressed by High-Dose Creatine Supplementation in Exercise-Training Rats

作　　者：李斌[1] 艾华[1] 李显[1] 

机构地区：[1]北京大学第三医院运动医学研究所,北京100083

出　　处：《中国运动医学杂志》2005年第3期297-301,共5页Chinese Journal of Sports Medicine

基　　金：2 0 0 0~ 2 0 0 1年国家体育总局应用基础研究项目 (编号 :0 10 6 1)资助。

摘　　要：目的:探讨补充大剂量肌酸对运动大鼠自身肌酸生物合成和体内肌酸代谢的影响。方法:给游泳训练大鼠补充肌酸,测定大鼠肾脏精氨酸-甘氨酸脒基转移酶(AGAT)活性、酶促反应产物胍乙酸含量、骨骼肌肌酸含量、血清肌酸和肌酐含量、血清肌酸激酶(CK)和乳酸脱氢酶(LDH)活性、大鼠游泳力竭时间。结果:补充超大剂量(6 .0g/kg/d)肌酸可引起大鼠腹泻,造成腓肠肌和比目鱼肌湿重显著下降(P <0 .0 5 ) ;补充相当于人体冲击剂量(1 5g/kg/d)和超大剂量肌酸,均可引起运动大鼠肾脏AGAT活性和肝脏胍乙酸含量明显下降(P <0 . 0 1) ;超大剂量补充肌酸引起游泳大鼠血清肌酐含量增加。此外,运动训练能提高肾脏AGAT活性和肝脏胍乙酸含量,促进内源性肌酸的合成。结论:超大剂量补充肌酸可抑制运动机体内源性肌酸的合成。建议实践中不宜超量超时补充肌酸,有必要对人体补充肌酸的冲击剂量(0 . 3g/kd/d或2 0g/d)的健康安全性进行深入研究。Objective The purpose of this study was mainly to study the effects of high - dose creatine supplementation on endogenous biosynthesis and metabolism of creatine in exercise - training rats. Methods After treated with variable doses of creatine, the activities of L - arginine： glycine amidinotransferase （AGAT）, the contents of gnanidinoacetic acid （GA） which is the enzymatic reaction product of AGAT in kidney , creatine concentration in skeletal muscles and serum, creatine kinase （CK） and lactate dehydrogenase （LDH） activities and creatinine levels in serum in the exercise - training and control rats were determined. Additionally, the exhaustive swim time of the rats was recorded. Results A very high dose （6.0g/kg/d） of creatine supplementation could cause diarrhea and markedly （P 〈 0.05） decrease wet weights of gastrocnemius and soleus muscles in the swim - training rats. The training rats following creatine supplementation at doses of 1.5g/kg/ d （equal to the loading dose for human） or 6.0g/kg/d had significantly （ P 〈 0.01 ） lower AGAT activity in kidney and gnanidinoacetic acid content in liver than the training rats without creatine supplement. The close of 6.0g/kg/d creatine supplementation could increase serum creatinine level （P 〈 0.01）. Additionally, the activity of the kidney AGAT and the gnanidinoacetic acid content in liver were significantly increased （ P 〈 0.01） among the swim- training rats. Conclusion High dose of creatine supplementation could inhibit endogenous biosynthetic system for creatine in exercise - training rats. It is suggested that athletes should supplement creatine within recommended dosing range. The healthy security of creatine loading close （0.3g/kd/d or 20g/d） for human needs further research.

关 键 词：补充肌酸 精氨酸-甘氨酸转脒基酶 运动 大鼠 血清肌酸 运动大鼠 生物合成 超大剂量 运动训练 内源性 

分 类 号：R87[医药卫生—运动医学]