Context: Acute hypoglycemia accelerates gastric emptying and increases cardiac contractility. However, antecedent hypoglycemia attenuates counterregulatory hormonal responses to subsequent hypoglycemia.
Objective: To determine the effect of antecedent hypoglycemia on gastric and cardiac responses to subsequent hypoglycemia in health.
Design: A prospective, single-blind, randomized, crossover study (performed at the Royal Adelaide Hospital, Adelaide, South Australia, Australia).
Patients: Ten healthy young men 18 to 35 years of age were studied for 36 hours on two occasions.
Interventions: Participants were randomly assigned to either antecedent hypoglycemia [three 45-minute periods of strict hypoglycemia (2.8 mmol/L] or control [three 45-minute periods of strict euglycemia (6 mmol/L)] during the initial 12-hour period. Participants were monitored overnight, and the following morning blood glucose was clamped at 2.8 mmol/L for 60 minutes and then at 6 mmol/L for 120 minutes. At least 6 weeks later participants returned for the alternative intervention. Gastric emptying and cardiac fractional shortening were measured with scintigraphy and two-dimensional echocardiography, respectively, on the morning of all 4 study days.
Results: A single, acute episode of hypoglycemia accelerated gastric emptying (P = 0.01) and augmented fractional shortening (P < 0.01). Gastric emptying was unaffected by antecedent hypoglycemia (P = 0.74) whereas fractional shortening showed a trend to attenuation (P = 0.06). The adrenaline response was diminished (P < 0.05) by antecedent hypoglycemia.
Conclusions: In health, the acceleration of gastric emptying during hypoglycemia is unaffected by antecedent hypoglycemia, whereas the increase in cardiac contractility may be attenuated.
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