Department of Physiology and Biochemistry, Faculty of Physical Education and Sport, Charles University in Prague, Prague, Czech Republic.
Physiol Res. 2013;62(6):721-9. doi: 10.33549/physiolres.932542. Epub 2013 Jul 17.
Creatine (Cr) is recommended as a dietary supplement especially for athletes but its therapeutic potential is also discussed. It is assumed that human body uses Cr for the formation of phosphocreatine, which is necessary for muscular work as a source of energy. Production of Cr in a body is closely connected to methionine cycle where guanidinoacetate (GAA) is in a final step methylated from S-adenosylmethionine (SAM). Increased availability of SAM for phosphatidylcholine (PC) and sarcosine synthesis can potentially stimulate endogenous production of betaine a thus methylation of homocysteine (HCy) to form methionine. Our subject who was methylenetetrahydrofolate reductase (MTHFR) 677TT homozygote lowered plasma HCy from 33.3 micromol/l to 17.1 micromol/l following one-month Cr supplementation (5 g/day) opposite to 677CC and CT genotypes whose HCy levels tended to increase (but still in normal ranges). We suppose that Cr supplementation stimulates pathways leading to production of sarcosine which can serve to regenerate tetrahydrofolate (THF) to form 5,10-methylene-THF. This could potentially increase MTHFR enzyme activity which may later result in increased HCy methylation. Cr supplementation significantly effects metabolism of one carbon unit and potentially lower body´s demands for methyl groups. This could be beneficial as in the case of reduced enzyme activity such as MTHFR 677C/T polymorphism.
肌酸（Cr）被推荐作为一种膳食补充剂，特别是对运动员，但它的治疗潜力也在讨论中。据认为，人体利用 Cr 来形成磷酸肌酸，磷酸肌酸是肌肉工作的能量来源。Cr 在体内的产生与蛋氨酸循环密切相关，其中胍基乙酸（GAA）在最后一步由 S-腺苷甲硫氨酸（SAM）甲基化。SAM 对磷脂酰胆碱（PC）和肌氨酸合成的可用性增加，可能会刺激甜菜碱的内源性产生，从而使同型半胱氨酸（HCy）甲基化为蛋氨酸。我们的研究对象是亚甲基四氢叶酸还原酶（MTHFR）677TT 纯合子，在补充 Cr（每天 5 克）一个月后，其血浆 HCy 从 33.3 微摩尔/升降低到 17.1 微摩尔/升，而 677CC 和 CT 基因型的 HCy 水平则趋于升高（但仍在正常范围内）。我们假设 Cr 补充刺激了产生肌氨酸的途径，肌氨酸可以再生四氢叶酸（THF）形成 5,10-亚甲基-THF。这可能会增加 MTHFR 酶的活性，从而导致 HCy 甲基化增加。Cr 补充显著影响一碳单位的代谢，并可能降低身体对甲基的需求。这可能是有益的，例如在酶活性降低的情况下，如 MTHFR 677C/T 多态性。
