Antecedent hypoglycemia does not alter increased epinephrine-induced lipolysis in type 1 diabetes mellitus

Type 1 diabetic subjects have decreased epinephrine responses to hypoglycemia that may be counterbalanced by increased beta-adrenergic sensitivity. The goal of this study was to determine whether type 1 diabetic subjects have increased metabolic response to epinephrine and to determine the effect of antecedent hypoglycemia on these responses. Muscular glucose uptake across the forearm (forearm glucose uptake, Fick principle) and lipolysis (free fatty acid and glycerol levels) were studied before and during a 4-hour euglycemic, hyperinsulinemic (40 mU x m(-2) x min(-1)) clamp with epinephrine infusion (0.015 microg x kg(-1) x min(-1)) over 3 hours. Subjects were studied twice, once with antecedent hypoglycemia (2.8 mmol/L for two 2-hour sessions) and once with antecedent euglycemia (5 mmol/L) the day prior. Free fatty acid and glycerol concentrations were higher, and total body glucose utilization and forearm glucose uptake during epinephrine were lower in diabetic than in control subjects (P < .05). Antecedent hypoglycemia had no effect. These results demonstrate that type 1 diabetic subjects have increased lipolysis and decreased glucose utilization in response to epinephrine. These effects are not altered by antecedent hypoglycemia.