Bagger JI, Grondahl MFG, Lund A, et al. - The present study was performed to explore the dose-response relationship for glucagon-like peptide 1 (GLP-1) on glucose-induced glucagon suppression in healthy individuals and patients with type 2 and type 1 diabetes. Researchers included 10 healthy individuals with normal glucose tolerance, 10 patients with type 2 diabetes, and 9 C-peptide–negative patients with type 1 diabetes who had undergone 4 separate stepwise glucose clamps (five 30-min steps from fasting level to 15 mmol/L plasma glucose) during simultaneous intravenous infusions of saline or 0.2, 0.4, or 0.8 pmol GLP-1/kg/min. During a stepwise glucose clam, the glucagonostatic potency of GLP-1 is preserved in patients with type 2 diabetes, whereas the individuals with type 1 diabetes were insensitive to the glucagonostatic effects of both glucose and GLP-1.