Specific binding of [ 3H]ouabain to heart is inhibited by long-chain fatty acids and alcohols

Abstract

Long-chain fatty acids and alcohols inhibit specific binding of [ 3H]ouabain to a particulate fraction from dog heart. The magnitude of inhibition increases with chain length, reaching a maximum with lauric acid, myristoleic acid and decanol in a series of saturated fatty acids, unsaturated fatty acids, and alcohols, respectively, followed by a decline with longer chain members of homologous series. Unsaturated fatty acids and alcohols are more inhibitory than their corresponding saturated congeners; in general, inhibitory potency is greater in cis than trans forms and increases with higher degree of unsaturation. Methyl esters of both saturated and unsaturated fatty acids tested were inactive at 10 −3 m or lower concentrations. The inhibition of ouabain binding by fatty acids and alcohols was specific and appears to be competitive. This study extends our earlier findings on the inhibitory activity of fatty acid fractions from bovine liver.