Reduced number of digitalis receptor sites in the hypertrophied pig myocardium.
Left ventricular hypertrophy was established in young pigs (35-40 kg) after 4 weeks of supravalvular aortic stenosis. Isolated sarcolemmal membrane fraction was characterized for specific 3H-ouabain binding. Analysis revealed a single class of receptor sites of 5.7 p moles/mg protein and a dissociation constant (Kd) of the order of 6.25 X 10(-8) M. Measurement of specific 3H-ouabain binding with sarcolemmal fraction isolated from hypertrophied heart revealed a 26% reduction of digitalis receptor after 4 weeks of aortic stenosis, without any significant change in the affinity of receptor sites. This change in the number of digitalis receptors was maintained between 4 and 8 weeks of aortic stenosis and may be an important adaptive mechanism.
D000818:Animals; D001024:Aortic Valve Stenosis; D006332:Cardiomegaly / Q000378:metabolism*; D004070:Digitalis / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000378:metabolism; D010946:Plants, Medicinal; D010947:Plants, Toxic; D011955:Receptors, Drug / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase; D013552:Swine; D013997:Time Factors
D011955:Receptors, Drug; C027082:digitalis receptor; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase