LACK OF EFFECTS OF ANGIOTENSIN-CONVERTING ENZYME (ACE-INHIBITORS ON GLUCOSE-METABOLISM IN TYPE-1 DIABETES

To evaluate the impact of ACE‐inhibitors on insulin‐mediated glucose uptake, glucoseinduced glucose uptake, and hepatic glucose production, a sequential glucose clamp was performed in eight normotensive Type 1 diabetic patients after 3 weeks of enalapril therapy 20 mg day−1 and during control conditions. The experiments were carried out in random order. Mean arterial blood pressure was significantly reduced during ACE‐inhibition (95 ± 3 (±SE) vs 84 ± 3 mmHg; p < 0.02), while blood glucose control as assessed by HbA1c was unaltered (7.9 ± 0.5 vs 7.6 ± 0.5%). The night prior to the study normoglycaemia was maintained by a Biostator. A two‐step hyperinsulinaemic euglycaemic clamp (insulin infusion rate 0.3 and 0.8 mU kg−1 min−1) was followed by a hyperinsulinaemic and hyperglycaemic clamp (insulin infusion rate 0.8 mU kg−1 min−1, plasma glucose 11 mmoll−1). Insulin concentrations were comparable with and without enalapril treatment. During the hyperinsulinaemic clamps isotopically determined glucose disposal was unchanged (low dose 2.5 ± 0.3, high dose 4.3 ± 0.7 vs 2.6 ± 0.3 and 4.3 ± 0.7 mg kg−1 min−1 enalapril vs control). Glucose‐induced glucose disposal (9.2 ± 1.2 vs 9.1 ± 1.2 mg kg−1 min1) was also similar, as were non‐protein respiratory exchange ratios (indirect calorimetry). Glucose production was not changed by enalapril. In conclusion, treatment with enalapril has no significant effect on glucose metabolism in Type 1 diabetes. 1990 Diabetes UK