THE EFFECTS OF INCREASING DOSES OF ENALAPRIL ON INSULIN SENSITIVITY IN NORMOTENSIVE NON-INSULIN-DEPENDENT DIABETIC SUBJECTS

Background: There are conflicting reports about the effects of ACE inh ibitors (ACEI) on insulin sensitivity and glycaemic control. Most stud ies have used a standard high dose of an ACEI but there have been no s tudies reported to establish whether any changes in glycaemic control or insulin sensitivity associated with ACEI are dose-related. Aim: To examine the effect of increasing doses of enalapril on insulin sensiti vity in normotensive non-insulin dependent diabetic subjects. Methods: The effects of increasing doses of enalapril on insulin sensitivity i n ten normotensive non-insulin dependent diabetic subjects were measur ed, using the hyperinsulinaemic isoglycaemic clamp technique. Followin g a baseline study, enalapril was commenced at 5 mg daily and increase d to 10 mg daily then 20 mg daily at 14 day intervals. Repeat studies were undertaken after 14 days at each dosage. Results: There was a sig nificant dose-related reduction of systolic blood pressure with enalap ril. In contrast enalapril at 5-20 mg daily produced no significant ch anges in insulin mediated glucose uptake (M-value) or insulin sensitiv ity index (ISI). Conclusions: These findings indicate that in this ins ulin resistant population of normotensive noninsulin dependent diabeti cs, angiotensin converting enzyme inhibition with enalapril has no sig nificant effect on insulin mediated glucose uptake.