The purpose of this study was to examine the effect of dietary creatine and leucine supplementation on protein synthesis and functional properties of skeletal muscle during 8 weeks of resistance exercise. Thirty two male Sprague-Dawley rat(5 weeks old) were randomly divided into four groups(8 rats per group): sedentary control group(CON), execise group(E), exercise with creatine supplementation group(EC), exercise with creatine, leucine supplementation group(ECL). Exercise groups were trained to climb a ladder with a weight secured to their tails(3day/week). The supplementation was administrated daily through oral gavage. Creatine supplementation was given at 250㎎/㎏/day. Creatine+leucine supplementation was given at 250+250㎎/㎏/day. All exercise groups presented significantly lower epididymal fat mass than CON(p<.05). E presented significantly higher plantaris mass than CON(p<.05). All exercise groups significantly presented higher FHL mass than CON(p<.05) and E presented higher FHL mass than EC, ECL(p<.05). EC, ECL presented significantly lower expression of Akt/PKB protein than CON, E(p<.05). There was no difference in the expression of mTOR protein. The results suggest that the creatine and leucine supplementation does not promote any additional hypertrophic effect on resistance trained skeletal muscle. But, creatine and leucine supplementation might have a potential benefit on skeletal muscle hypertrophy through the activation of protein synthesis.
