GCG and Hyperglycemia: This glucose concentration is in fact close to the fed plasma glucose levels in CTL mice (Figures S1A and S1B; see also https://phenome.jax.org/measures/32301) and similar to that found in Fh1βKO mice before hyperglycemia and the defects of glucagon secretion developed (Figures 1A, S1A, and S1B).