1192-P: Robust Arginine-Stimulated Glucagon Secretion in Patients with Type 1 Diabetes Independent of Diabetes Duration, Age, HbA1c, and Beta-Cell Secretory Capacity

In type 1 diabetes (T1D), the counterregulatory glucagon response to hypoglycemia disappears over time. It remains unknown whether this is due to lack of glucagon production or represents a malfunctioning stimulus-secretion coupling in pancreatic alpha cells. Arginine test (5 g of arginine infused intravenously (iv) over 1 minute after an overnight fast) with frequent measurements of plasma glucagon and serum C-peptide concentrations over 30 minutes was performed in 80 patients with T1D (19/61 females/males, age 49 (22-74) years (median (range)), duration 20 (2-46) years, BMI 28 (22-44) kg/m2, HbA1c 8.2 (7.5-10) %). The interrelationship between the arginine-induced glucagon response and demographic, clinical and biochemical parameters was evaluated using a stepwise approach in two multiple linear regression analysis models with glucagon area under curve (AUC) and Cmax, respectively, as dependent parameter. Mean baseline plasma glucagon concentrations amounted to 10.6±5.5 pmol/L (mean±SD). Overall, robust arginine-induced glucagon responses were observed (AUC: 499±209 pmol/L × min; Cmax: 41.0±17.7 pmol/L) independently of diabetes duration, age, HbA1c and beta cell secretory capacity. Fasting plasma glucagon and waist-to-hip ratio predicted the glucagon response in both models. When leaving out fasting plasma glucagon of the models, fasting low-density lipoprotein cholesterol and alanine aminotransferase as well as eGFR also predicted the glucagon response. In conclusion, glucagon secretory capacity in patients with T1D as assessed by iv arginine test seems preserved independently of diabetes duration, age, HbA1c and beta cell secretory capacity positioning pharmaceutical restoration of the glucagon counterregulatory response to hypoglycemia as an attractive therapeutic strategy for the protection of insulin-induced hypoglycemia.