Ventricular beta-adrenoceptors in adriamycin-induced cardiomyopathy in the rabbit.

beta-Adrenoceptor concentrations have been measured in ventricles of rabbits with adriamycin-induced cardiomyopathy. Despite considerable cardiac hypertrophy (1.6 +/- 0.7 mean +/- S.E.M. g ventricle/kg body wt, n = 6; to 2.2 +/- 0.1) no change in beta-adrenoceptor density was observed (33.8 +/- 2.0 fmol/mg protein in membranes from cardiomyopathic rabbits compared with 36.8 +/- 3.0 for controls). Furthermore, no alteration in the profiles of high affinity agonist binding was observed, and the receptor interaction with the adenylate cyclase stimulatory coupling factor was unimpaired. These results indicate that, despite the marked changes which occur during the development of this model of low-output heart failure, the cardiac beta-adrenoceptor systems are normal.