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目的:探讨大剂量、短时间补充肌酸停止后,大鼠内源性肌酸生物合成的恢复。方法:大鼠补充大剂量(3.0g/kg/d)肌酸1周后停止,动态观察内源性肌酸生物合成代谢途径中限速酶活力和主要代谢物质含量的变化。结果:大剂量、短时间补充肌酸引起的肾脏精氨酸-甘氨酸脒基转移酶(AGAT)活力下降,可在停补肌酸后8天内恢复正常;补充肌酸引起的肾脏和肝脏胍乙酸含量降低也分别于停补肌酸后4天和8天内恢复正常;补充肌酸导致的各组织器官肌酸含量升高均在8天内恢复正常,其中肾脏1天,血清3～4天,比目鱼肌4天,腓肠肌8天;升高的血清肌酐含量于1天内恢复正常。组织肌酸激酶(creatinekinase,CK)活力未受到补充肌酸的影响。结论:停止大剂量、短时间补充肌酸后,大鼠自身的肌酸生物合成到8天左右可逐渐恢复正常。这表明,大剂量、短时间补充肌酸对内源性肌酸合成的抑制作用可在去除抑制因素后较短时期内得到逆转。
OBJECTIVE: To investigate the recovery of endogenous creatine biosynthesis in rats after high-dose and short-term creatine supplementation is stopped. Methods: Rats were given a large dose of creatine (3.0g / kg / d) for one week and then stopped to observe the changes of the rate-limiting enzyme activity and the content of major metabolites in endogenous creatine biosynthesis pathway. RESULTS: The renal arginine-glycine amidotransferase (AGAT) activity induced by high-dose and short-term creatine supplementation decreased, which returned to normal within 8 days after stopping creatine supplementation. Supplementation of creatine induced renal and hepatic guanidine Reduced levels also returned to normal within 4 days and 8 days after stopping creatine supplementation respectively. Creatine supplementation increased the levels of creatine in all tissues and organs within 8 days, with 1 day of kidney, 3 to 4 days of serum, Muscle 4 days, gastrocnemius 8 days; elevated serum creatinine levels within 1 days returned to normal. Tissue creatine kinase (CK) activity was not affected by creatine supplementation. CONCLUSION: After stopping high-dose and short-term creatine supplementation, rats’ creatine biosynthesis gradually returns to normal after about 8 days. This indicates that inhibition of endogenous creatine synthesis by high-dose, short-term creatine supplementation may be reversed in a shorter period of time after removal of the inhibitory factor.