Аннотация:General principles of radioreceptor assay pertinent to the membrane receptor preparations are discussed. The effects of the following factors are analyzed: concrete conditions of the assay, ligands affinity for receptors, the effects of relative contribution of nonspecific binding and ligands concentrations on the precision and sensitivity of the assay, as well as on the maximal measurable concentration found from a given standard curve and on the range of reliable concentrations for a compound under study. The performance of the assay is shown to be the better, the lower is the concentration of the labeled ligand, the higher its affinity for the receptor and the lower is the nonspecific binding contribution.