-GPA feeding leads to reductions in skeletal muscle phosphagen concentrations and has been used as a tool with which to study the effects of energy charge on skeletal muscle metabolism. Supplementing standard rodent diets with -GPA leads to increases in mitochondrial enzyme content in fast but not slow twitch muscles from male rats. Given this apparent discrepancy between muscle types we used -GPA feeding as a model to study signaling pathways involved in mitochondrial biogenesis. We hypothesized that -GPA feeding would result in a preferential activation of p38 MAPK and AMPK signaling and reductions in RIP140 protein content in triceps but not soleus muscle. Despite similar reductions in high energy phosphate concentrations, 6 weeks of -GPA feeding led to increases in mitochondrial proteins in triceps but not soleus muscles. Differences in the response of mitochondrial proteins to -GPA feeding did not seem to be related to a differential activation of p38 MAPK and AMPK signaling pathways or discrepancies in the induction of PGC-1 and PGC-1. The protein content and expression of the nuclear co-repressor RIP140 was reduced in triceps but not soleus muscle. Collectively our results indicate that chronic reductions in high energy phosphates lead to the activation of p38 MAPK and AMPK signaling and increases in the expression of PGC-1 and in both soleus and triceps muscles. The lack of an effect of -GPA feeding on mitochondrial proteins in the soleus muscles could be related to a fiber type specific effect of -GPA on RIP140 protein content