Abstract
In order to establish a radioreceptorassay for catecholamines, mainly based on the method of Lefkowitz et al, we have investigated the properties of the microsome fraction of bovine myocardium as catecholamine receptors, and obtained the following results.
1) The binding of catecholamines to the microsome fraction is biphasic and the affmity constants of high and low bindings 1.56×107M-1 and 1.00×104M-1, respectively.
2) The binding site of catecholamines to receptors is thought to be the catechol nucleus.
3) Radioreceptorassay is sensitive but not so specific, becuase many compounds with catechol nucleus showed cross-reaction.
4) Cross-reactivity of adrenergic blocking agents suggest that our purified bovine myocardium microsome fraction contains alpha-adrenergic receptors.
