Steady-state Exendin-9 concentrations (Figure 1H) were ∼0.4 μg/mL (∼120 nmol/L), ∼2-fold above the binding affinity of Exendin-9 for GLP1R in human insulinoma cells (Waser and Reubi, 2011). This evidence concerns the gene GLP1R and pancreatic insulinoma.