Stimulation of erythrocyte and renal Na+,K+-adenosine triphosphatase activity by antidigoxin antibody in normal rats.
1. A circulating ouabain-like factor which inhibits the Na+,K(+)-pump has been implicated in volume-expanded states. To assess the role of this putative factor in normovolaemic rats, we measured erythrocyte and renal Na+,K(+)-adenosine triphosphatase activity after the infusion of a mixture of high-affinity digoxin-binding Fab fragments (Digibind) capable of removing digoxin from pump sites. 2. Compared with either saline (vehicle) or sheep immunoglobin G, infusion of the antidigoxin antibody caused a moderate increase of Na+,K(+)-adenosine triphosphatase activity in the erythrocyte (saline 348 +/- 12; immunoglobulin G 339 +/- 16; antidigoxin antibody 432 +/- 22 nmol h-1 mg-1; P less than 0.005 by analysis of variance) and a larger increase in the renal cortex (saline 9.7 +/- 0.9; immunoglobulin G 9 +/- 1.4; antidigoxin antibody 24.3 +/- 1.8 mumol h-1 mg-1; P less than 0.0005 by analysis of variance) without a change in blood pressure. 3. These results are consistent with the presence of a digoxin-like inhibitor of the Na+,K+-pump in normal rats.
Wagener
O E
OE
Section of Nephrology/Hypertension, Veterans Administration Lakeside Medical Center, Chicago, Illinois 60611.
Mujais
S K
SK
Del Greco
F
F
Quintanilla
A P
AP
D000818:Animals; D001794:Blood Pressure; D004077:Digoxin / Q000276:immunology*; D004789:Enzyme Activation; D004912:Erythrocytes / Q000201:enzymology*; D007140:Immunoglobulin Fab Fragments / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D007668:Kidney / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood / Q000378:metabolism*
D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; C050199:digoxin antibodies Fab fragments; D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase