Erythrocyte insulin receptors remain intact through three days of storage.

The status of the erythrocyte insulin receptor was investigated prior to and during storage at 4C in acid-citrate dextrose (ACD) solution. The receptors on cells that were obtained from both resting and exercised fasting subjects and stored for up to three days in ACD were unchanged as evaluated by both maximal specific hormone binding and the concentration of insulin required to one half maximally inhibit specific binding. These findings indicate, therefore, that the binding of insulin to its receptor on erythrocytes can be assayed in samples of stored blood and that this assay reflects the status of the receptor at the time of sampling.