The effect of DEX (100 μmol/l for 24 h) and leucine treatment (5 mmol/l or 10 mmol/l or 15 mmol/l for 1 h) on protein synthesis (A), and the protein expression of mTOR (B), P-mTOR (C), p70s6k (D), P-p70s6k (E), 4EBP1 (F), P-4EBP1 (G), AMPK (H) and P-AMPK (I) in C2C12 myoblasts. The protein level was quantified by normalizing total proteins with β-actin, and by normalizing phosphorylated proteins with their total pairs. The values shown are the means±S.E.M. (n=6); a, b: means with different letters are significantly different (P<0.05).