Double antibody immunoassay of immunoreactive insulin (IRI) in sera and plasma obtained with 12.5 and 50 IU heparin per ml or with EDTA 5 mg per ml of blood did not give significant differences from the identical blood samples. But in the presence of higher insulin concentrations (100 and 500 IU per ml of blood), the determined IRI values were significantly higher. If EDTA plasma were obtained with 25 mg EDTA per ml of blood, the IRI level would lower significantly. To eliminate the presence of human plasma proteins, IRI determinations were made from buffer containing only bovine albumin as protein. Under these conditions, the presence of higher heparin concentrations gave higher IRI values, but EDTA had no influence on the return to the original insulin concentration. These results suggested that heparin acts on the reaction between insulin and insulin binding antibodies by lowering it, independently of the presence of plasma proteins. The lower IRI values in the presence of EDTA should be connected with a plasma factor.
|Number of pages||6|
|Publication status||Published - Dec 1 1974|
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