Characterization of beta-adrenergic receptors in rat ovary

Specific beta-adrenergic receptors were characterized in rat ovary, using an in vitro receptor binding assay with [3H]dihydroalprenolol. The ligand was bound to a single class of saturable and high affinity receptors (dissociation constant = 3.5 nM and maximum capacity = 3.4 pmol/g tissue). In competition studies, the binding was stereoselective for the (-)-isomer of isoproterenol. Known beta-adrenergic agonists displaced the ligand from ovarian receptors with the following order of potency: isoproterenol greater than epinephrine much greater than norepinephrine, which is typical for a beta 2-adrenergic receptor.