Insulin binding and degradation by human erythrocytes and erythrocyte membranes

Conclusions

By the current results there is evidence that the insulin degrading enzyme activity of the erythrocytes is not located on the inner or outer surface of the plasma membrane but is exclusively cytosolic. On the other hand, specific insulin binding to erythrocytes and erythrocyte membranes has been demonstrated and it could be supposed that the insulin binding region of the plasma membrane is not associated with an insulin degrading activity.

In comparison to erythrocytes unsealed and sealed ghosts bound an equal amount of ¹²⁵I-insulin. Since there is binding but not degradation of insulin the membranes of erythrocytes might be a useful tool for the investigation of insulin internalization.