SOLID-PHASE RADIOIMMUNOASSAY OF INSULIN

Abstract

ABSTRACT A solid-phase radioimmunoassay of insulin was developed using the plastic tube technique in which the inner walls of the tubes were coated with insulin antibodies. The binding of 125I-insulin to the adsorbed antibody was shown to be quantitatively inhibited with the non-radioactive insulin present in the samples tested. The optimal conditions were determined for a) labelling of small amounts (3 μg) of insulin with radioactive iodine, b) coating of plastic tubes with insulin antisera and γ-globulin fractions, c) the stability of coated tubes with insulin antibodies and d) radioimmunoassay of insulin. The reproducibility of the coated test tube technique for insulin determination is adequate from a clinical point of view and the ease with which this test is performed is advantageous from a practical point of view.