CHARACTERIZATION OF THE BETA(2) ADRENOCEPTORS OF DOG LIVER

The beta-adrenoceptors present in dog liver were characterized by radi oligand binding techniques. [H-3]Dihydroalprenolol bound with high aff inity (K-D 0.9 nM) to a relatively low number of sites (approximate to 68 fmol/mg protein) in partially purified dog liver plasma membranes. These sites were characterized by binding competition; the orders of affinity were: (a) for agonists: (-)isoproterenol greater than or equa l to salbutamol > epinephrine greater than or equal to terbutaline > n orepinephrine > (+)isoproterenol and (b) for antagonists: propranolol > ICI 118551 much greater than metoprolol much greater than atenolol. These data indicate that dos liver expresses beta-adrenoceptors of the beta(2) subtype. Copyright (C) 1996 Elsevier Science Inc.