Sympathetic hyperactivity in Wistar rats with insulin-resistance

In an attempt to know the effect of sustained hyperinsulinemia on sympathet ic function, plasma norepinephrine (NE) and glucose levels were measured in Wistar rats with insulin resistance. Both the basal plasma glucose and the plasma NE levels in insulin-resistant rats were markedly higher than that obtained in normal or streptozotocin (STZ)-induced diabetic rats. Treatment with guanethidine and prazosin reversed these sympathetic hyperactive resp onses in insulin-resistant rats. Moreover, increase of plasma insulin in ra ts receiving an intraperitoneal glucose challenge test confirmed the mediat ion of endogenous insulin in this sympathetic hyperactivity. These results suggest an increase of sympathetic activity in insulin-resistant state that may be related to the hypertension-prone associated with diabetes mellitus in clinics. (C) 1998 Elsevier Science B.V. All rights reserved.