Chronic intravenous glucose infusion causes moderate hypertension in rats

We have reported that chronic insulin infusion increases mean arterial pres sure (MAP) in rats. In those studies, glucose was coinfused to prevent hypo glycemia, but it is possible that the glucose infusion rate may have exceed ed the rate actually required to prevent hypoglycemia. If true, then the gl ucose infusion alone should have a similar effect, and this study tested th at hypothesis. In six rats (insulin group) instrumented with artery and vei n catheters, insulin was infused for 7 days intravenously (iv) at 1.5 mU/kg /min together with glucose iv at 18.6 mg/kg/min. Seven other rats (glucose group) received the same glucose infusion for 7 days but without iv insulin . MAP increased significantly in both groups, from 98 +/- 3 and 96 +/- 2 mm Hg to 107 +/- 5 and 104 +/- 3 mm Hg in the insulin and glucose groups, res pectively, and the renal and hormonal changes were similar to those previou sly reported during insulin infusion. There were no significant differences between the two groups for any variable measured. These data indicate that the sugar intake provided by the glucose infusion essentially mimics the r esponse to our insulin and glucose infusion protocol, and that similar mech anisms underlie the renal and cardiovascular responses to each protocol. (C ) 2000 American Journal of Hypertension, Ltd.