A simple radioreceptor assay was established with sensitivity and accuracy sufficient
to detect concentrations of insulin in human peripheral sera. The radioreceptor assay
was carried out at 4 °C using rabbit erythrocyte membranes and 125I-insulin. In the absence of native insulin, approximately 31 % of the total 125I-insulin concentration was bound to erythrocyte membranes. Fourty-six per cent of
this binding was displaced by 312 μU/ml of native insulin. The precision expressed
as coefficient of variation was 3 to 21 % of the mean for the within-assay, and 1
to 21 % for the between-assay, respectively. The recovery of standard porcine insulin
added to the serum was 105 % on the average. Insulin values in 24 samples of human
sera measured by the present assay agreed well with immunoreactive insulin values.
Radioreceptor-Assay
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Insulin
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Rabbit Erythrocyte Membrane
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Human Serum
