mTOR phosphorylation in muscle of 6- and 12-wk-old mdx and B10 mice. Phosphorylation of the mammalian target of rapamycin (mTOR), which is an indicator of its activation, was analyzed by Western blot of total muscle protein extracts of tibialis anterior (TA) and diaphragm (Dia) of 6- and 12-wk-old mdx mice and was compared to age-matched wild-type C57BL/10 (B10) mice. Ratios of phosphorylated mTOR (p-mTOR) to total mTOR (t-mTOR) are shown for 6-wk-old (A) and 12-wk-old (B) TA muscle and for 6-wk-old (C) and 12-wk-old (D) Dia muscle. Values presented in graphs (A-D) were calculated by measuring average blot intensity of the labeling for each tissue type. A representative image of Western blot labeling of p-mTOR and t-mTOR in TA and Dia muscles of 6-wk-old mdx and B10 mice is shown (E). GAPDH is shown as a loading control. n = 5 for B10 groups and n = 4 for mdx groups. *P < 0.05.