A study of lipid effects on the digoxin immunoassay and on the binding to and activity of Na+/K+-ATPase.
The present study has examined the cross-reactivity of fatty acids and mono- and di-glycerides in the fluorescence polarization immunoassay for digoxin. The ability of these compounds to inhibit 86Rb uptake by the erythrocyte as well as their ability to displace 3H-ouabain from membrane-bound dog kidney ATP-ase was also assessed. Some unsaturated fatty acids (palmitoleic, palmitelaidic, oleic, linoleic, linolelaidic, linolenic, gamma-linolenic and arachidonic) were found to cross-react significantly in the digoxin immunoassay and to inhibit 3H-ouabain binding to membrane-bound Na+/K+-ATPase. Of the monoglycerides studied mono-11-eicosenoin was found to cross-react in the digoxin immunoassay, inhibit red cell 86Rb uptake and displace 3H-ouabain from its receptor, membrane-bound Na+/K+-ATPase. Two other monoglycerides, 1-monolinoleoyl and 1-monolinolenoyl glycerides, were able to displace 3H-ouabain from membrane-bound Na+/K+-ATPase, but had no effect on the digoxin immunoassay or on red cell 86Rb uptake.
D000818:Animals; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D003429:Cross Reactions; D004075:Diglycerides / Q000494:pharmacology; D004077:Digoxin / Q000032:analysis*; D004285:Dogs; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D005227:Fatty Acids / Q000494:pharmacology; D005454:Fluorescence Polarization / Q000379:methods; D005455:Fluorescent Antibody Technique; D005989:Glycerides / Q000494:pharmacology; D006801:Humans; D007554:Isotopes / Q000378:metabolism; D007668:Kidney / Q000648:ultrastructure; D008055:Lipids / Q000494:pharmacology*; D010042:Ouabain / Q000378:metabolism; D011453:Prostaglandins / Q000494:pharmacology; D012413:Rubidium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism* / Q000502:physiology
D004075:Diglycerides; D005227:Fatty Acids; D005989:Glycerides; D007554:Isotopes; D008055:Lipids; D011453:Prostaglandins; D010042:Ouabain; D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium