Figure 3. Effects of digoxin and acute exercise on [³H]‐ouabain binding site content in human skeletal muscle, measured after clearance of bound digoxin by F_ab (OB+F_ab).

The [³H]‐ouabain binding site content measured after prior incubation in Digibind F_ab (OB+F_ab), after 14 days of oral digoxin (DIG) or placebo (CON), and expressed relative to (A) muscle wet weight and (B) muscle protein content. Biopsies were taken at rest (Rest), after cycling for 10 min at 33% ${\mathrm{V}}_{{\mathrm{O}}_2\mathrm{peak}}$ and 10 min at 67% ${\mathrm{V}}_{{\mathrm{O}}_2\mathrm{peak}}$ (67%), immediately following cycling to fatigue at 90% ${\mathrm{V}}_{{\mathrm{O}}_2\mathrm{peak}}$ (Fatigue) and at 3 h after exercise (+3 h). Data are mean (SD), n = 10; the exact number of data measurement points was 76. Individual data are plotted using different symbols and connected by dashed lines. Time effects are indicated as differences between the times connected by horizontal bar, ^* P < 0.05, ^† P < 0.01; a trend to higher OB+F_ab (per g protein) at 67% vs. rest was found (P = 0.087, 21%). No significant digoxin effects (P = 0.809, P = 0.376), or time × treatment interaction (P = 0.591, P = 0.861) were found for OB+F_ab expressed per g wet weight, or per g protein, respectively.