This result appears to support an additive role for creatine on the actions of antioxidant enzymes. Physical training, as demonstrated by Halliwell and Gutteridge [51], activates transcription factors such as AMPK, which activate CAT mRNA, thereby stimulating protein synthesis and possibly increasing CAT activity. The ability of CrS to also exert this effect remains controversial. According to Sestile et al. [4], creatine has neutralizing effects on ROS production that do not interfere on the action of antioxidant enzymes. However, the increase in CAT activity observed in this study is attributed to the formation of H2O2 by SOD. According to Halliwel and Gutteridge

[51], the chemical interaction this website of H2O2 at the catalase active site involves the transfer of a hydrogen ion between the two oxygen atoms, causing a heterolytic cleavage with water and oxygen end products. The findings in our study of increased H2O2 levels in trained and supplemented animals combined with RO4929097 ic50 the neutralizing action of creatine on this ROS may explain

the reduced oxidative damage seen with increased CAT activity. In contrast, the amounts of GSH and GSSG as well as the ratio between GSH/GSSG did not differ between the study groups. GSH has a central role in the biotransformation and elimination of xenobiotics, and protects cells against oxidative stress [52]. To maintain the protective activity of glutathione as expressed by the reduction of oxidizing species and consequent oxidation of GSH to GSSG, GSH must be regenerated through the catalytic cycle [52]. In summary, our study results demonstrate that creatine supplementation acts in an additive manner to physical training to increase antioxidant enzymes in rat liver. More studies are needed to expand our knowledge of the antioxidant effects of creatine and to investigate creatine’s little-known effects on other body tissues. Acknowledgements The authors are grateful for the technical support of Clarice

Y. Sibuya and José Roberto R. da Silva who contributed greatly to this Project. Funding This study was supported by “The State of São Paulo Foundation for Research Support” (FAPESP – Proc. 2009/52063-0). References 1. Gama MS: Efeitos da creatina sobre desempenho aeróbio: uma revisão sistemática. Revista Brasileira de Nutrição Esportiva 2011, 5:182–190. ZD1839 cell line 2. Pereira Júnior M, Moraes AJP, Ornellas FH, Gonçalves MA, Liberalli R, Navarro F: Eficiência da suplementação de creatina no desempenho físico humano. Revista Brasileira Prescrição e Fisiologia do Exercício 2012, 6:90–97. 3. Cruzat VF, Rogero MM, Borges MC, Tirapegui J: Aspectos atuais sobre estresse oxidativo, exercícios físicos e suplementação. Rev Bras Med Esporte 2007, 13:336–342.CrossRef 4. Sestili P, Martinelli C, Bravi G, Piccoli G, Curci R: Creatine supplementation affords cytoprotection in oxidatively injured cultured mammalian cells via direct antioxidant activity. Free Radic Biol Med 2006, 40:837–849.PubMedCrossRef 5.