Definition of a beta-adrenergic receptor population in skeletal muscle: [¹²⁵I]hydroxybenzylpindolol binding

1. 1. The ligand [¹²⁵I]hydroxybenzylpindolol has been used to characterize a set of binding sites in rat skeletal muscle. 2. 2. The binding assay described is linear to 70 μg of protein and maintains equilibrium for several hours. 3. 3. A Scatchard analysis indicates an interaction between a homogeneous ligand and a single set of identical, independent binding sites. 4. 4. The number of binding sites is 8.7 × 10^-14mols/mg protein with a first thermodynamic association constant of 1.83 × 10¹⁰ M^-1. 5. 5. A stereospecific interaction is seen between the natural ligand and the binding sites. 6. 6. The data suggests that this set of sites represent the beta-adrenergic receptor of skeletal muscle.