Endogenous inotropic substance from heart tissue has digitalis-like properties.
In the past few years, we developed an extraction procedure which we successfully used to isolate a crude fraction containing digitalis-like substance (DLS) from porcine left ventricular tissue. In this study, the crude fraction was found to cross-react with digoxin antibodies and showed immunoreactivity of 4.25 +/- 0.6 ng digoxin equivalent/ml. On further purification of the crude fraction using silica gel G column chromatography, a fraction C was obtained, which was highly positive inotropic on canine trabeculae and it dose-dependently inhibited ouabain sensitive 86Rb+ uptake in rat heart slices. A 50% inhibition of uptake was obtained by 25 microliters of fraction C. Fraction C also inhibited canine kidney Na+, K(+)-ATPase (Sigma, U.S.A.) dose-dependently and a 50% inhibition of this enzyme required 17 microliters of fraction C. Ashing of the fraction C at 500 degrees C resulted in loss of inotropic and enzyme inhibitory activities, indicating an organic nature of the unknown digitalis-like substance.
Khatter
J C
JC
Department of Medicine, University of Manitoba, Winnipeg, Canada.
Agbanyo
M
M
Navaratnam
S
S
D000818:Animals; D000906:Antibodies / Q000276:immunology; D001692:Biological Transport; D001798:Blood Proteins / Q000276:immunology / Q000494:pharmacology*; D002298:Cardenolides; D002316:Cardiotonic Agents; D002853:Chromatography, Liquid; D003429:Cross Reactions; D004071:Digitalis Glycosides / Q000276:immunology / Q000494:pharmacology*; D004077:Digoxin; D004285:Dogs; D007668:Kidney / Q000201:enzymology; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012503:Saponins; D015222:Sodium Channels / Q000187:drug effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D013552:Swine
D000906:Antibodies; D001798:Blood Proteins; D002298:Cardenolides; D002316:Cardiotonic Agents; D004071:Digitalis Glycosides; D012503:Saponins; D015222:Sodium Channels; C034504:digoxin-like factors; D010042:Ouabain; D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase