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目的 :探讨大剂量补充肌酸抑制大鼠内源性肌酸合成和影响代谢的时间效应。方法 :大剂量补充肌酸 (3 0g/kg/d)不同时间后 ,测定大鼠肾脏和胰脏精氨酸 -甘氨酸脒基转移酶 (AGAT)活性、酶促反应产物胍乙酸含量、血清和骨骼肌的肌酸含量和肌酸激酶活性、血清肌酐水平 ,分析补充肌酸的时间 -效应关系。结果 :补充大剂量肌酸 4天后 ,大鼠腓肠肌湿重下降 ;大剂量补充肌酸可在 12小时抑制肾脏和胰脏的AGAT活性 ,使胍乙酸生成量明显减少。补充肌酸 0 5～ 1天内 ,A GAT活性下降幅度最大 ;补充时间越长 ,AGAT活性抑制越明显 ,胍乙酸生成越少。大剂量补充肌酸可引起大鼠腓肠肌和血清肌酸含量增加 ,腓肠肌CK活性出现升高趋势 ,还引起血清肌酐水平呈快速而短暂的升高。结论 :大剂量补充肌酸可在短时间内对自身肌酸合成体系造成抑制。
Objective: To investigate the time effect of high dose creatine supplementation on endogenous creatine synthesis and metabolism in rats. Methods: The arginine-glycine amidotransferase (AGAT) activity in rat kidney and pancreas was determined after high-dose creatine supplementation (30g / kg / d) for a long time. The contents of guanidinium acetate, Creatine content and creatine kinase activity of skeletal muscle, serum creatinine level, and the time-effect relationship of creatine supplementation. RESULTS: After 4 days of high-dose creatine supplementation, the wet weight of gastrocnemius in rats decreased. The high-dose creatine supplementation inhibited the AGAT activity in kidney and pancreas at 12 hours, and the production of guanidinium acetate was significantly reduced. Within 5 to 1 days of supplementation of creatine, A GAT activity decreased the most. When the supplementation time was longer, the inhibition of AGAT activity was more obvious and the guanidine acetate generation was less. High doses of creatine supplementation can cause gastrocnemius and serum creatine levels in rats increased, CK activity of gastrocnemius muscle increased, but also caused a rapid and transient increase in serum creatinine. CONCLUSIONS: High-dose creatine supplementation can inhibit its own creatine synthesis system in a short period of time.