常规方法(冲击量+维持量)补充肌酸对内源性肌酸合成代谢的影响

目的:探讨常规方法(冲击量 维持量)补充肌酸对大鼠自身肌酸生物合成代谢的影响.方法:冲击剂量(1.5g/kg/d)补充肌酸1周和维持剂量(0.15g/kg/d)补充肌酸1月、2月后,分别测定大鼠肾脏精氨酸-甘氨酸脒基转移酶(AGAT)活性,肾脏和肝脏胍乙酸含量,肾脏、骨骼肌和血清肌酸含量,血清和骨骼肌肌酸激酶(CK)活性及血清肌酐水平.结果:冲击量及维持量补充肌酸均可导致大鼠肾脏AGAT活性以及肾脏和肝脏胍乙酸含量降低,引起肾脏肌酸含量明显增加,肾脏和血清肌酸含量与AGAT酶活性呈明显负相关.冲击期血清肌酐水平显著升高,但在维持期恢复正常.结论:常规方法(冲击量 维持量)补充肌酸可显著抑制内源性肌酸的合成.

Effects of Creatine Supplementation with Loading Doses plus Maintaining Doses on the Endogenous Biosynthesis and Metabolism of Creatine in Rats

Objective To investigate the effects of creatine (Cr) supplementation with loading doses plus maintaining doses on the endogenous biosynthesis and metabolism of Cr in rats. Methods After supplementing Cr with loading dose for 1 week and maintaining dose for 1 month and 2 months in the rats, L-arginine:glycine amidinotransferase (AGAT) activity in kidney, guanidinoacetic acid (GA) contents in kidney and liver, creatine contents in kidney, skeletal muscle and serum, creatine kinase (CK) activities in skeletal muscle and serum, and creatinine level in serum were determined. Results AGAT activities in kidney decreased, GA contents in kidney and liver decreased, and the Cr contents in kidney increased at both the loading term and the maintaining term of Cr supplementation. The Cr concentrations in kidney and serum had markedly negative correlation with ATAT activities in kidney. The serum creatinine levels rose significantly during the loading period and went back to normal during the maintaining period. Conclusions The Cr supplementation with loading doses plus maintaining doses could suppress the endogenous biosynthesis of Cr.