Fasting Lowers Glucagon Levels Under Basal Conditions and During Insulin-Induced Hypoglycemia in Individuals With Type 1 Diabetes

Fasting is associated with increased risk of hypoglycemia in patients with type 1 diabetes (T1D); however, little is known about how the counterregulatory responses to low blood sugar are affected under these metabolic conditions. During insulin-induced hypoglycemia, fasting (compared with eating normal meals for breakfast and lunch) glucagon concentrations were lower by 42% and endogenous glucose production by 47% in individuals with T1D. The secretion of other counterregulatory hormones during hypoglycemia was not affected by fasting (e.g., epinephrine, norepinephrine, cortisol). Fasting diminishes glucagon levels under hypoglycemic conditions in those with T1D, which may increase their susceptibility to hypoglycemia.