Vanadyl sulfate prevents fructose-induced hyperinsulinemia and hypertension in rats

Abstract

To determine whether insulin resistance and hyperinsulinemia are causally related to fructose-induced hypertension, we used vanadyl sulfate, a drug that improves insulin sensitivity in rats. Chronic oral vanadyl treatment was initiated in 6-week-old male Sprague-Dawley rats. One week after vanadyl was started, rats were fed either normal rat chow or a fructose-enriched diet. Plasma glucose and insulin levels and systolic blood pressure were measured weekly for 4 weeks. Fructose feeding induced hyperinsulinemia (fructose-fed, 366.6±8.4 versus control, 276±10.8 pmol/L, P .05). Restoration of plasma insulin in the fructose-vanadyl-treated rats to pretreatment levels (daily subcutaneous Ultralente insulin, 14 000 pmol/kg per day) reversed the effects of vanadyl on blood pressure (vanadyl-treated plus insulin, 170±9.8 mm Hg), without a change in plasma glucose. We conclude that hyperinsulinemia, secondary to insulin resistance, may contribute to the development of fructose-induced hypertension and that vanadyl sulfate prevents fructose-induced increases in plasma insulin levels and blood pressure.