Dissociation of digoxin-like immunoreactivity and Na+,K+-ATPase inhibitory activity in rat plasma.
We measured endogenous digitalis-like factor (EDF) in rat plasma during acute saline infusion by two different procedures. Na+,K+-ATPase inhibitory activity in the rat plasma significantly increased during saline loading (7.8 +/- 2.2 vs 2.5 +/- 0.9%, with and without acute saline loading, respectively, p less than 0.05). On the other hand, the plasma digoxin-like immunoreactivity significantly decreased during acute saline loading (16.9 +/- 1.6 vs 32.0 +/- 2.8 pg digoxin equivalents/ml, with and without acute saline loading, respectively, p less than 0.01). These results indicate that the major substances detected by digoxin-like immunoreactivity and direct Na+,K+-ATPase inhibitory activity are completely different, at least in rat plasma.
Yamada
K
K
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Goto
A
A
Ishii
M
M
Yoshioka
M
M
Sugimoto
T
T
D000818:Animals; D001798:Blood Proteins; D002298:Cardenolides; D004077:Digoxin; D008297:Male; D051381:Rats; D012503:Saponins; D012965:Sodium Chloride / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*
D001798:Blood Proteins; D002298:Cardenolides; D012503:Saponins; C034504:digoxin-like factors; D012965:Sodium Chloride; D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase