The beta-adrenergic receptor of newborn mouse skin

Binding of the potent beta-adrenergic antagonist [125I]iodohydroxybenzylpindolol ([125I]IHYP) to particulate preparations from newborn mouse skin was characterized. A number of criteria were used to establish that binding occurred to specific, high affinity beta-adrenergic receptors in the skin preparations. Thus specific binding (that displaced by 10 micrometer concentrations of the beta-adrenergic antagonist (-)propranolol) reached equilibrium in 15--20 min, was saturable (ligand concentration for half-maximal saturation, 0.25 nM) and freely reversible. Stereoselectivity of binding was demonstrated by the observation that displacement of [125I]IHYP by (-)propranolol occurred at concentrations at least 100 times lower than with (+)isoproterenol. Displacement was also observed with the beta-adrenergic agonists (-)isoproterenol, (-)epinephrine and (-)norepinephrine, but not with the alpha-adrenergic antagonist phentolamine.