Interaction of cardiodigin, endogenous inhibitor of Na +,K +-ATPase, with antidigoxin and antidigitoxin antibodies

• Published in: Biochemical and biophysical research communications Vol. 129; no. 2; pp. 553 - 559
• Main Authors: Fagoo, M., Godfraind, T.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 14.06.1985; Elsevier
• Subjects: Animals; Antibodies - immunology; Applied sciences; Biological Products - immunology; Biological Products - metabolism; Cardiac Glycosides; Cross Reactions; Digitoxin - immunology; Digoxin - immunology; Exact sciences and technology; Guinea Pigs; Immunochemistry; Myocardium - immunology; Myocardium - metabolism; Other techniques and industries; Sodium-Potassium-Exchanging ATPase - antagonists & inhibitors
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(85)90187-1

The present study was undertaken to further characterize the immunoreactivity of cardiodigin, digitalis-like factor present in mammalian tissues. Guinea-pig heart extracts purified by reverse-phase low pressure and high pressure liquid chromatographies were analysed for their cross-reactivity with antidigitoxin and antidigoxin antibodies. The putative digitalis-like factor showed an affinity about 10 times higher for antidigoxin antibodies than for antidigitoxin antibodies. EC 50 ratios (digoxin/digitoxin assay) determined at two purification steps were different from those of digoxin and digitoxin. These results show that cardiodigin presents molecular determinants recognizable by antidigoxin and antidigitoxin antibodies but that it is a chemical entity different from these well known cardioactive steroids.