Insulin binding to liver plasma membranes from rats rendered diabetic by alloxan. A kinetic demonstration of two classes of binding sites in equilibrium with each other.

The association of 125I-labelled insulin with liver plasma membranes from diabetic rats was consistent with more than one compartment of binding. After a short association period, insulin dissociation comprised rapid and slow phases. After a long association period, dissociation was only at a slow rate. Lower-affinity hormone-receptor complexes were converted to higher-affinity complexes as the time of occupancy lengthened.