Insulin-induced hypoglycemia accelerates gastric emptying of solids and liquids in long-standing type 1 diabetes.
BACKGROUND
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
The objective was to determine the effects of acute hypoglycemia on gastric emptying in long-standing type 1 diabetes and evaluate whether the response to hypoglycemia is influenced by the rate of gastric emptying during euglycemia and/or autonomic dysfunction.


METHODS
Gastric emptying of a solid/liquid meal (100 g (99m)Tc-minced beef and 150 ml 67Ga-EDTA-labeled water) was measured by scintigraphy on 2 separate days, during hypoglycemia and euglycemia.


METHODS
These studies took place at the Department of Nuclear Medicine, Positron Emission Tomography, and Bone Densitometry at the Royal Adelaide Hospital.


METHODS
Twenty type 1 patients (4 female, 16 male; age, 45.9 +/- 2.3 yr; duration of known diabetes, 18.0 +/- 2.7 yr) were recruited from outpatient clinics and the Diabetes Centre at the Royal Adelaide Hospital.


METHODS
Hypoglycemia (approximately 2.6 mmol/liter) 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.


METHODS
The main outcome measure was gastric emptying during hypoglycemia when compared with euglycemia.


RESULTS
Twelve 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, percentage retention at 100 min, r = -0.52, P < 0.05; 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 long-standing type 1 diabetes, even in those patients with delayed emptying, and is likely to be an important mechanism in the counter-regulation of hypoglycemia.
Russo
Antonietta
A
Department of Medicine, Royal Adelaide Hospital, University of Adelaide, Frome Road, Adelaide, South Australia, 5005, Australia.
Stevens
Julie E
JE
Chen
Richard
R
Gentilcore
Diana
D
Burnet
Richard
R
Horowitz
Michael
M
Jones
Karen L
KL
D000328:Adult; D001794:Blood Pressure; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy*; D004326:Drinking; D004435:Eating; D005260:Female; D005710:Gallium Radioisotopes; D005746:Gastric Emptying / Q000187:drug effects / Q000502:physiology*; D015309:Glucose Clamp Technique; D006339:Heart Rate; D006801:Humans; D007003:Hypoglycemia / Q000139:chemically induced / Q000209:etiology / Q000503:physiopathology*; D007004:Hypoglycemic Agents / Q000009:adverse effects*; D007328:Insulin / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D013667:Technetium
D005710:Gallium Radioisotopes; D007004:Hypoglycemic Agents; D007328:Insulin; D013667:Technetium