title: [Characterization of an endogenous factor with digitalic activity in the guinea pig heart (II): Binding to a receptor].
abstract: In this work we continue the studies on the presence of an endogenous digitalis-like factor in mammals. A water extract from guinea pig heart was partially purified by liquid chromatography. The extract displaced (3H)ouabain specific binding to guinea pig heart Na,K-ATPase yielding a displacement curve parallel to that observed when digoxin was used as displacing agent. The data suggest that the activity of the extract was due to the presence of a factor that recognizes the digitalis binding site but not to ions nor lipids. Furthermore, the extract cross-reacted with antidigoxin antibodies in a manner similar to the specific antigens. These results support the hypothesis of the existence of an endogenous ligand of the digitalis receptor in mammals that could be a physiological regulator of the sodium pump.
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D004071:Digitalis Glycosides / Q000032:analysis*; D006168:Guinea Pigs; D009206:Myocardium / Q000032:analysis* / Q000378:metabolism; D010042:Ouabain / Q000378:metabolism; D011863:Radioimmunoassay; D011955:Receptors, Drug / Q000032:analysis* / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase
chemical_list: D004071:Digitalis Glycosides; D011955:Receptors, Drug; C028996:cardiac glycoside receptors; C027082:digitalis receptor; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase
vernacular_title: Caracterización de un factor endógeno con actividad digitálica en el corazón de cobayo (II): Unión al receptor.