The glucagonostatic potency of GLP-1 was investigated in C-peptide-negative adults with long-standing T1D (average HbA1c 7.7%, BMI 29 kg/m2) by using stepped hyperglycemic clamps (steady-state glycemia 90 to 270 mg/dL) along with increasing infusions of GLP-1 (161). Here, GLP1R is linked to type 1 diabetes mellitus.