Ilkov A T, Damianova M P, Koparanova O L
Acta Diabetol Lat. 1977 Jan-Apr;14(1-2):9-17. doi: 10.1007/BF02624659.
Polyethyleneglycol precipitation of insulin antibodies and insulin-antibody complexes is associated with co-precipitation of part of the free insulin. The recovery of free insulin was found to depend both on the quantity and quality of the antibodies and varied between 94% and 40%. Thus, the concentrations of free and total insulin may be lowered up to 2.5-fold in different sera containing endogenous antibodies. A critical evaluation of these results led to the development of a more reliable method for the assay of total and free insulin, based on individual radioisotopic determinations of the recovery of insulin extracted by PEG. The recovery of insulin added to sera containing antibodies as determined by the present method is within the range of 100 +/1 2.5%. In sera not containing antibodies total insulin concentration was found to be up to 5-times higher than that of IRI and to reach values above 250 muU/ml whereas whereas indirect IRI (i-IRI) may increase over 25 times with age.
胰岛素抗体及胰岛素 - 抗体复合物的聚乙二醇沉淀与部分游离胰岛素的共沉淀有关。发现游离胰岛素的回收率既取决于抗体的数量和质量，回收率在94%至40%之间变化。因此，在含有内源性抗体的不同血清中，游离胰岛素和总胰岛素的浓度可能会降低至2.5倍。对这些结果的严格评估导致开发出一种更可靠的总胰岛素和游离胰岛素测定方法，该方法基于对聚乙二醇提取的胰岛素回收率的个别放射性同位素测定。用本方法测定添加到含抗体血清中的胰岛素回收率在100±2.5%范围内。在不含抗体的血清中，发现总胰岛素浓度比免疫反应性胰岛素（IRI）高5倍，可达250 μU/ml以上，而间接IRI（i - IRI）可能随年龄增长增加25倍以上。
