Human myometrial adrenergic receptors: Identification of the beta-adrenergic receptor by ( super(3)H)dihydroalprenolol binding

The radioactive beta-adrenergic antagonist ( super(3)H) dihydroalprenolol (DHA) binds to particulate preparations of human myometrium in a manner compatible with binding to the beta-adrenergic receptor. The binding of DHA is rapid, readily reversible, high affinity, low capacity and stereoselective. Adrenergic agonists competed for DHA binding sites in a manner compatible with beta-adrenergic interactions and mirrored beta sub(2) pharmacologic potencies: isoproterenol > epinephrine >> norepinephrine. Binding of DHA to human myometrial beta-adrenergic receptors provides a tool which may be used in the examination of gonadal hormonal modification of adrenergic response in human uterus as well as in the analysis of beta-adrenergic agents as potentially useful tocolytic agents.