Figure 2: Activation of PKA increases nuclear Flag-NT-PGC-1α. (a) Representative images of Flag-NT-PGC-1α in a control fiber (control) and in another fiber after 1 h treatment with 1 mM dbcAMP in culture medium in the tissue culture incubator (dbcAMP). Scale bar, 10 μm. (b) The n/c fluorescence ratio of Flag-NT-PGC-1α in muscle fibers with (dbcAMP) or without (control) dbcAMP treatment. n/c values from 20 nuclei from 20 randomly selected fibers were averaged to give the mean value for each group. Asterisk indicates statistical significance between groups at .