Inhibition of the na,k-atpase by digoxin and its relation with energy
expenditure and nutrient oxidation rate.
Lyon, X., Y. Schutz, T. Buclin, E. J[acute]equier, and O. D[acute]eriaz.
Institute of Physiology and Division of Clinical Pharmacology, Faculty of
Medicine, University of Lausanne, 1005 Lausanne, Switzerland.
APStracts 2:0009E, 1995.
This study investigates the effects of digoxin, an inhibitor of the sodium
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 per day digoxin or a
placebo two days before indirect calorimetry measurements. Digoxin induced a
0.22 +/- 0.07.kJ.min-1 or 3.8+/- 1.5 % (mean +/- SEM, P=0.01) decrease in RMR
and a 0.40 +/- 0.14 kJ.min-1 (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. Since 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.
Received 8 August 1994; accepted in final form 12 January 1995.
APS Manuscript Number E309-4.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.