STUDIES ON THE INTRINSIC ACTIVITY (EFFICACY) OF HUMAN ADRENERGIC-RECEPTORS - COEXPRESSION OF BETA(1) AND BETA(2) REVEALS A LOWER EFFICACY FOR THE BETA(1) RECEPTOR
L. Birnbaumer et al., STUDIES ON THE INTRINSIC ACTIVITY (EFFICACY) OF HUMAN ADRENERGIC-RECEPTORS - COEXPRESSION OF BETA(1) AND BETA(2) REVEALS A LOWER EFFICACY FOR THE BETA(1) RECEPTOR, Texas Heart Institute journal, 21(1), 1994, pp. 16-21
Through co-expression of the human beta1 and beta2 adrenergic receptor
s in a single tester cell (the murine L fibroblast) and through assayi
ng the effect of the beta1 and beta2 selective blockers CGP 20712A and
ICI 118551 on isoproterenol-stimulated adenylyl cyclase, it is shown
that the maximal stimulation achievable with a given cell density of b
eta1 adrenergic receptor is less than that obtained with the same dens
ity of the beta2 adrenergic receptor It is concluded that the efficacy
of the 2 receptors differs in that the beta1 adrenergic receptor has
a lower efficacy (or intrinsic activity) than does the beta2 adrenergi
c receptor.