Comparison of in Vivo Post-Exercise PCr Recovery and Basal ATP Synthesis Flux for the Assessment of Skeletal Muscle Mitochondrial Function

Nicole Martina Adriana van den Broek¹, Jolita Ciapaite¹, Klaas Nicolay¹, Jeanine J. Prompers¹

The interpretation of basal ATP synthesis flux (V_ATP) measured by ³¹P saturation transfer (ST) is not straightforward. In this study, post-exercise PCr recovery and ST-based V_ATP were compared in a rat model of mitochondrial dysfunction. Treatment with complex 1 inhibitor DPI induced mitochondrial dysfunction, as evidenced by a decreased oxygen consumption rate in isolated mitochondria and a decreased in vivo post-exercise PCr recovery. Interestingly, no significant difference in V_ATP was observed between DPI-treated rats and controls. This shows that ST measurements in rest do not necessarily reflect intrinsic mitochondrial function, but more likely the ATP demand of the cell.