Quality control of insulin radioreceptor assay for human erythrocytes. Effect of ageing of mono-125I-Tyr-A14-insulin preparation.
The quality control of insulin radioreceptor assay for human erythrocytes is based on the storage of erythrocyte preparations in Hepes buffer of pH 8.0, containing 10 g/l of albumin and 20 mmol/l of glucose. The change of erythrocytes into spherocytes and crenated cells reduces the apparent number of insulin receptors in a relatively constant way by less than 8% a week after 10 days of storage. At the same time the dissociation constants of the insulin-receptor complex increase rapidly. Thus the use of a preparation must be limited to controlling the determination of the insulin binding sites of erythrocytes, and not to the measurement of the affinities of the receptors. When mono-125I-Tyr-A14-insulin gets old, a slow decrease in the insulin binding sites can be measured, but the dissociation constants of the insulin receptor complex are not affected.
D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000031:analogs & derivatives* / Q000097:blood; D007457:Iodine Radioisotopes; D011786:Quality Control; D011869:Radioligand Assay / Q000592:standards*; D011972:Receptor, Insulin / Q000032:analysis*; D013048:Specimen Handling; D013997:Time Factors
D007328:Insulin; D007457:Iodine Radioisotopes; C029491:insulin, 3-iodo-Tyr(A14)-; D011972:Receptor, Insulin