Original Contributions Nitric Oxide Does Not Participate in the Metabolic Effects of Exogenous Bradykinin In Fructose-Fed Rats

The study was carried out to demonstrate the effects of bradykinin (BK) on hypertension, hyperinsulinemia, and hypertriglyceridemia in fructose-fed rats, and to determine whether these actions are mediated through nitric-oxide (NO) formation. Eighteen rats, rendered hypertensive, hyperinsulinemic, and hypertriglyceridemic by a fructose-enriched diet, were studied. BK (0.2 mg/day) was infused intravenously using osmotic pumps attached by a catheter to the jugular vein of 12 rats for 12 days. BK was administered either alone (n 5 6) or with concomitant inhibition of NO synthase (n 5 6). Six untreated rats served as control. Measurements of systolic blood pressure (indirect method) and levels of insulin and triglyceride in serum were taken every second day. BK infused chronically, induced a marked fall in all parameters as early as the second day of infusion: in blood pressure from 152 6 7 to 126 6 12 mmHg, in insulin from 8.7 6 2.9 to 4.6 6 5.4 pg/mL, and in triglyceride from 308 6 94 to 76 6 19 mg/dL. No such reduction was seen in untreated animals. When BK was administered concur-rently with NO synthase inhibitor, blood pressure rose significantly, reaching very high values at the end of treatment. However, the reduction in insulin and triglyc-eride levels induced by BK was not affected. The capacity of BK to enhance reduction in hyperinsulin-emia and hypertriglyceridemia in the fructose-fed rats is not mediated by NO formation. Whether this action of BK is related to a direct effect of this peptide remains to be deter