Figure 6.

Effects of dietary soy glycinin protein on IGF-1 signaling in denervated muscle. The right and left legs of C57BL/6 mice were subjected to denervation and sham operation, respectively. The mice were fed with 20% casein (control) or 20% soy glycinin diet from 1 week before denervation till the end of the experiment. TA muscles were isolated at days 1, 3, 3.5, and 4 after denervation. (a) Homogenates of TA muscles isolated were subjected to immunoblotting (IB) for IRS-1 and actin on the indicated days after denervation. (b–d) Homogenates of TA muscles isolated from mice fed with control or 20% glycinin diet at 3.5 days after denervation were subjected to IB for IRS-1 and actin (b) and phosphorylated Akt-1 and total Akt-1 (d). The densitometric analysis of these images was performed with ImageJ software. Data are mean ± SD (n = 3). *P < 0.05 versus sham operation; ^# P < 0.05 versus control diet in denervated muscle. Immunoprecipitates (IP) from the TA muscles with an anti-IRS-1 antibody were subjected to IB for ubiquitin (c). Representative findings of five experiments with matching results. (e) Expression levels of MAFbx/atrogin-1, MuRF-1, Cbl-b, and GAPDH (internal control) transcripts in TA muscle analyzed by real-time RT-PCR. The level of each transcript was normalized to sham-operated mice fed with control diet. Data are mean ± SD (n = 5). *P < 0.05 versus sham operation; ^# P < 0.05 versus control diet in denervated muscle.