Context: The rate of gastric emptying of carbohydrate is a major determinant of postprandial glycemia. In healthy subjects and patients with uncomplicated type 1 diabetes, there is evidence that gastric emptying may be accelerated by insulin-induced hypoglycemia.

Objective: To determine the effects of acute hypoglycemia on gastric emptying in longstanding type 1 diabetes, and evaluate whether the response to hypoglycemia is influenced by the rate of gastric emptying during euglycemia and/or autonomic dysfunction.

Design: Gastric emptying of a solid/liquid meal (100 g ^99mTc-minced beef and 150 ml ⁶⁷Ga-EDTA labeled water) was measured by scintigraphy on two separate days, during hypoglycemia and euglycemia.

Setting: Department of Nuclear Medicine, PET and Bone Densitometry at the Royal Adelaide Hospital.

Patients: 20 type 1 patients (4 female, 16 male, age 45.9 ± 2.3 yr and duration of known diabetes 18.0 ± 2.7 yr) were recruited from outpatient clinics and the Diabetes Centre at the Royal Adelaide Hospital.

Intervention: Hypoglycemia (2.6 mmol/L) was established 15 min before, and maintained for 45 min after meal consumption. On one of the days, autonomic nerve function was evaluated using cardiovascular reflex tests.

Main Outcome Measure: Gastric emptying during hypoglycemia when compared with euglycemia.

Results: 12 of the 20 subjects had autonomic neuropathy. Gastric emptying of both solid (P < 0.001) and liquid (P < 0.05) was faster during hypoglycemia. The magnitude of this acceleration was greater when the rate of gastric emptying during euglycemia was slower (solid: % retention at 100 min, r= -0.52, P < 0.05 and liquid: 50% emptying time, r 0.82, P < 0.0001, but not influenced by autonomic nerve function.

Conclusions: Insulin-induced hypoglycemia accelerates gastric emptying of solids and liquids in longstanding type 1 diabetes even in those patients with delayed emptying, and is likely to be an important mechanism in the counter-regulation of hypoglycemia.