title: Evidence that mammalian lignans show endogenous digitalis-like activities.
abstract: Enterolactone, a lignan that has been identified in biological samples from man and several mammals, shares with ascorbic acid and cardiac glycosides a gamma-butyrolactone. It displaces 3H-ouabain from its binding sites on cardiac digitalis receptor and inhibits, dose dependently, the Na+, K+-ATPase activity of human and guinea-pig heart. The time dependence of this inhibition resembles that of dihydroouabain, a cardiac glycoside in which the lactone ring does not contain conjugated double bonds. The active concentrations of enterolactone as inhibitor of Na+,K+-ATPase are in the 10(-4) M range and, at those concentrations, the cross-reactivity with antidigoxin antibodies is low. Lignans may contribute to the putative digitalis-like activity found in tissues, blood and urine of several mammals including man.
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001667:Binding, Competitive; D003429:Cross Reactions; D004077:Digoxin / Q000276:immunology; D005663:Furans / Q000502:physiology*; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D017705:Lignans; D009206:Myocardium / Q000201:enzymology; D010042:Ouabain / Q000031:analogs & derivatives / Q000378:metabolism; D011863:Radioimmunoassay; D011955:Receptors, Drug / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*
chemical_list: D005663:Furans; D017705:Lignans; D011955:Receptors, Drug; C027082:digitalis receptor; C000977:dihydroouabain; D010042:Ouabain; D004077:Digoxin; D000254:Sodium-Potassium-Exchanging ATPase; D015107:4-Butyrolactone; C029497:2,3-bis(3'-hydroxybenzyl)butyrolactone