A solid-phase competitive radioimmunoassay for the insulin receptor.
A radioimmunoassay for the insulin receptor has been developed. In this assay, unlabeled receptor competes with 125I-labeled receptor for binding to monoclonal anti-receptor antibodies immobilized on microtiter wells coated with affinity-purified anti-mouse immunoglobulin G. This assay was highly reproducible and could detect 7 ng (14 fmol) of insulin receptor. By utilizing monoclonal antibodies to various antigenic regions of the receptor, different parts of the receptor molecule could be examined. By utilizing antibodies to the cytoplasmic domain of the receptor, an assay was developed which was not influenced by the presence of insulin and could equally detect the insulin receptor from different species (rat and human) and different tissues (placenta and brain). By utilizing antibodies to an autophosphorylation site of the receptor, the assay was shown capable of detecting the extent of phosphorylation of the receptor. Finally, this assay was utilized to monitor the decrease in insulin receptors in lysates of insulin-treated human lymphocytes. This radioimmunoassay should be useful for monitoring both the number and status of the insulin receptor under a variety of physiological conditions.
D000818:Animals; D000911:Antibodies, Monoclonal; D001667:Binding, Competitive; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D010766:Phosphorylation; D010920:Placenta / Q000032:analysis; D011247:Pregnancy; D011863:Radioimmunoassay / Q000379:methods*; D051381:Rats; D011972:Receptor, Insulin / Q000032:analysis* / Q000276:immunology
D000911:Antibodies, Monoclonal; D011972:Receptor, Insulin