Figure 1. Response of ACTOne GCGR cell line & parental cell line to glucagon. ACTOne GCGR cells and parental cells (AG-10200-200) were plated overnight in 20 µl culture medium on a BD Biocoat 384 well plate. The next day, cells were dye-loaded with 20 µl/well of 1X Dye-loading solution (ACTOne Membrane Potential Assay Kit). After 2 hours of incubation at room temperature, two readings were obtained prior to and 30 min after the addition of glucagon. Ratios of the two readings (F/F0) are plotted in the figure. A. Dose response curve of glucagon in ACTOne GCGR cell line. EC50 = 2.99 pM in the presence of PDE inhibitor Ro20-1724, and EC50 = 29.4 pM in the absence of Ro20-1724 (data not shown). B. Parental cells do not respond to glucagon.