(A) CRISPR strategy for deletion of G3R1 exon 2, and genotyping indicating successful creation of a mouse lines with >80% deletion of G3R1. WT = Wild type genotyping, KO = Knockout genotyping. (B) Intraperitoneal glucose tolerance test of G3R1-KO mice, and both wild type and heterozygous littermates at 8-weeks of age. +/+ = 8, +/− = 4, −/− = 4. (C) Random blood glucose levels measured at 8-weeks of age. +/+ = 5, +/− = 5, −/− = 7. Error bars indicate standard error of the mean. Immunofluorescence staining of 8-week old pancreas from WT and G3R1-KO mice for (D) INSULIN and GLUCAGON, (E) INSULIN and MAFA, and (F) SYNAPTOPHYSIN and PDX1, as well as DAPI. Images shown are representative.