Increased number of beta-adrenergic receptors in the hypertrophied myocardium.
Development of cardiac hypertrophy is associated with depletion of endogenous catecholamine stores and increased inotropic response to exogenous catecholamines. A biochemical basis for these changes is provided by the observation that the number of cardiac beta-adrenergic receptors - as reflected in specific [3H]dihydroalprenolol binding - is increased in hypertrophy without a change in the affinity of dihydroalprenolol for the binding sites or in the capacity of isoproterenol to displace dihydroalprenolol. This change in beta-receptor numbers may be an important adaptive mechanism for preserving the contractile performance of the hypertrophied myocardium.
D000526:Alprenolol / Q000031:analogs & derivatives*; D000818:Animals; D001667:Binding, Competitive; D006332:Cardiomegaly / Q000378:metabolism*; D004082:Dihydroalprenolol / Q000378:metabolism*; D007545:Isoproterenol / Q000378:metabolism; D008297:Male; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D000526:Alprenolol; D007545:Isoproterenol