AJP - Endocrinology and Metabolism, Vol 268, Issue 6 E1051-E1056, Copyright © 1995 by American Physiological Society
Inhibition of Na(+)-K(+)-ATPase by digoxin and its relation with energy expenditure and nutrient oxidation rate
X. Lyon, Y. Schutz, T. Buclin, E. Jequier and O. Deriaz
Institute of Physiology, Faculty of Medicine, University of Lausanne, Switzerland.
This study investigates the effects of digoxin, an inhibitor of the Na+
pump (Na(+)-K(+)-ATPase), on resting metabolic rate (RMR), respiratory
quotient (RQ), and nutrient oxidation rate. Twelve healthy male subjects
followed a double-blind protocol design and received either 1 mg/day
digoxin or a placebo 2 days before indirect calorimetry measurements.
Digoxin induced a 0.22 +/- 0.07 kJ/min or 3.8 +/- 1.5% (mean +/- SE, P =
0.01) decrease in RMR and a 0.40 +/- 0.13 kJ/min (P = 0.01) decrease in fat
oxidation rate, whereas carbohydrate and protein oxidation rates did not
change significantly. A dose-response relationship between serum digoxin
and RQ was observed. These results suggest that digoxin reduces not only
RMR but also fat oxidation rate by mechanisms that remain to be elucidated.
Because a linkage and an association between genes coding the
Na(+)-K(+)-ATPase and the RQ have been previously observed, the present
demonstration of an effect of Na(+)-K(+)-ATPase inhibition on fat oxidation
rate strengthens the concept that the activity of this enzyme may play a
role in body weight regulation.
