Lack of effect of insulin on glucose utilization of the hypothalamus in normotensive and hypertensive rats

Hypertension is frequently associated with insulin resistance and enhanced sympathetic activity supposedly mediated by an effect of the hormone on the hypothalamus. In this study we sought to determine whether insulin modifie s the functional activity of the hypothalamus and other brain areas of spon taneously hypertensive (SHR) and normotensive WKY rats. The study was carri ed out in control and hyperinsulinemic, normoglycemic rats. insulin plasma levels were increased to 198 +/- 10 (WKY) or 220 +/- 10 mu units/ml (SHR). Brain functional activity was evaluated by the 2-[C-14]deoxyglucose method for measuring local rates of glucose utilization. The results show that ins ulin has no effect on any of the brain areas examined including the hypotha lamus, of both WKY and SHR rats. The two strains of rats have comparable ce rebral metabolic rates also under basal conditions. (C) 2000 Elsevier Scien ce Ireland Ltd. All rights reserved.