Pressor recovery after acute stress is impaired in high fructose-fed Lean Zucker rats

Insulin resistance is a powerful predictor of cardiovascular disease; however, the mechanistic link remains unclear. This study aims to determine if early cardiovascular changes associated with short-term fructose feeding in the absence of obesity manifest as abnormal blood pressure control. Metabolic dysfunction was induced in Lean Zucker rats by short-term high-fructose feeding. Rats were implanted with telemetry devices for the measurement of mean arterial blood pressure (MAP) and subjected to air jet stress at 5 and 8 weeks after feeding. Additional animals were catheterized under anesthesia for the determination of MAP and blood flow responses in the hind limb and mesenteric vascular beds to intravenous injection of isoproterenol (0.001-0.5 mu m), a beta-adrenergic agonist. Metabolic dysfunction in high-fructose rats was not accompanied by changes in 24-h MAP. Yet, animals fed a high-fructose diet for 8 weeks exhibited a marked impairment in blood pressure recovery after air-jet stress. Dose-dependent decreases in MAP and peripheral blood flow in response to isoproterenol treatment were significantly attenuated in high-fructose rats. These data suggest that impaired blood pressure recovery to acute mental stress precedes the onset of hypertension in the early stages of insulin resistance. Further, blunted responses to isoproterenol implicate beta(2)-adrenergic sensitivity as a possible mechanism responsible for altered blood pressure control after short-term high-fructose feeding.