【摘要】 目的 :探讨大剂量、长时间补充肌酸对大鼠自身肌酸生物合成过程和肌酸代谢的影响。方法 :测定不同剂量补充肌酸 4周后大鼠肾脏的精氨酸 -甘氨酸脒基转移酶 (AGAT)活性和酶促反应产物胍乙酸含量、骨骼肌肌酸含量、血清肌酸激酶活性和肌酐水平。结果 :补充 4周不同剂量的肌酸后 ,大鼠体重有增加的趋势 ,同时腓肠肌湿重显著增加 (P <0 0 5 ) ,但 6 0g/kg组大鼠的体重和腓肠肌湿重低于其它剂量组。肾脏AGAT活性和胍乙酸含量有不同程度的降低 (P <0 0 1) ,补充剂量越大 ,降低程度越明显。结论 :大剂量、长时间补充肌酸可显著影响内源性肌酸的合成。超大剂量补充肌酸还会造成腹泻和骨骼肌量丢失。研究结果提示 ,补充肌酸应适量适时 ,不可长时间大剂量或超大剂量使用。更多还原

【Abstract】 Objective The purpose of this study was mainly to investigate the effects of chronic creatine (Cr) supplementation with different high doses on the endogenous biosynthesis and the metabolism of Cr in rats. Methods After creatine supplementing with high different doses for 4 weeks in the rats, the activities of L-arginine:glycine amidinotransferase (AGAT) and the contents of guanidinoacetic acid (GA) which is the enzymatic reaction product of AGAT in kidney and pancreas, the Cr concentrations in skeletal muscle, the creatine kinase (CK) activities and the creatinine levels in serum were determined. Results The body weight had a trend to increase and the wet weight of gastrocnemius muscle rose markedly (P<0.05) following Cr supplementation for 4 weeks in all groups of rats. However, the increased weights in the extra large dose group (6.0g/kg/d) were smaller than other groups (P<0.01). The AGAT activity and the GA content were significantly decreased (P< 0.01) in kidney in all groups of the rats. The higher the doses, the lower the AGAT activities and the GA contents. Conclusion Chronic supplementation of Cr at high dose can markedly affect the endogenous biosynthetic system of Cr in rats and the diarrhea and loss of muscle weight can be caused by an extra large dose of Cr supplementing. The results suggest that athletes should not load Cr by using high or extra high dose for longer period.更多还原