Abstract: Objective To observe the effect of endurance training or resistance training on the expression of IGF-1、MGF、MyoD and myogenin mRNA in gastrocnemius muscle. and to explore its role in the activation of muscle satellite cells. Methods 21 SAMP8 senile male mice were randomly distributed into three groups sedentary (CON, n=7) , endurance training group (n=7), resistance training groups (n=7). After 8wk training, gastrocnemius muscles were excised and muscle-wet weight and body mass (BM) are weighed and analyzed by real-time PCR. Results The ratio of muscle wet weight and BM (RM) of resistance training group showed significant differences when compared with that of the endurance group or control group ,8wk endurance training or resistance training resulted in an increase in mRNA levels of IGF-1、MGF、MyoD and myogenin, whereas two training groups have no significant difference except IGF-1mRNA which were significantly higher in resistance training group than those in endurance group. Conclusion Resistance training is better than endurance training in maintaining muscle quality effect. Two different exercise ways might be through the MGF which represent potential mediators implicated in the regulation of hypertrophy during exercise to activate the muscle satellite cells.

Key words: hypertrophy, IGF-1, MRFs, endurance training, resistance training