EFFECT OF INSULIN ON LOCAL AND TISSUE ACE ACTIVITY IN DIABETIC RATS

The precise mechanisms of vascular diseases in insulin dependent diabetes mellitus (IDDM) are not clearly understood. There are evidences of alteration in mechanisms involved in regulating vascular tone including increased ACE activity in some tissues. To investigate the effect of insulin treatment on these changes this study was performed. Three groups of 8 male Sprauge Dawely rats including control (C) and two diabetic groups (D, IT) were used in this study. Diabetes was induced by injection of 60 mg/kg STZ ip. After induction of diabetes IT group were treated with insulin (10 units/kg/day s.c.) for four weeks. The control group and the untreated diabetic group were treated with the same amount of Saline and for the same time. ACE activity was determined by HPLC method. 4 weeks after induction of diabetes, SBP and ACE activity in serum, lung, heart and aorta increased in D group compared to control rats. Insulin treatment reversed these changes to normal values in IT group. It is concluded that increased ACE activity could contribute to the development of diabetic vasculopathy and ACE reducing activity of insulin may be partially involved in decrease of cardiovascular complications in diabetes.