Receptor binding assays

The binding of insulin, insulin glargine, glargine M1 metabolite, A21Gly,DiD-Arg and IGF-1 to insulin receptor isoform A (IR-A) and IR-B were analysed using a competitive binding assay, using methods as previously described [8, 9], except that for these assays the plasma membranes were enriched from Chinese hamster ovary cells overexpressing either human IR-A or IR-B, and competitive binding assays were performed using 110 pmol A14[¹²⁵I]-insulin.