Figure 8.

Schematic summary of the proposed mechanism of the suppressed hypertrophic response to CB in SOL (left), compared to TA muscle (right). This scheme illustrates the proposed relationship between PDE4 expression and Epac1‐mediated skeletal muscle hypertrophy via activation of Akt/mTOR and CaMKII/HDAC4 signaling. PDE4 expression in SOL muscle (left) is greater than that in TA (right) and this is considered to result in increased cAMP hydrolysis, and thus a lower tissue concentration of cAMP, which may be insufficient to induce activation of hypertrophic signaling mediated by Epac1 and its downstream Akt/S6K1 and CaMKII/HDAC4 signaling pathways in SOL muscle.