Effects of antihypertensive drugs on blood pressure and metabolic alterations in the fructose-induced hypertensive rat.

Fructose feeding induces a moderate increase in blood pressure (BP) levels in normal rats, which is associated with insulin resistance, hyperinsulinemia, and hypertriglyceridemia. Increased vascular resistances in skeletal muscle have been proposed to contribute to BP elevation and insulin resistance in this animal model. To further explore the mechanisms underlying the fructose-induced hypertension in rats, the effects of quinapril and diltiazem on BP, renal function, plasma levels of glucose, insulin, and triglycerides, and insulin resistance were studied. Male Sprague-Dawley rats were fed for 4 weeks with diets containing 60% fructose or 60% starch and received quinapril or diltiazem in the drinking water. Fructose-fed rats showed higher BP and plasma levels of insulin and triglycerides when compared to controls. Treatments with quinapril or diltiazem prevented BP elevation and reduced elevated plasma insulin levels in fructose-fed rats. Plasma glucose and insulin levels were higher (P < .05) in fructose-fed rats than in controls at 15, 30, and 60 min after oral glucose load. Treatments with either quinapril or diltiazem prevented the exaggerated plasma insulin and glucose levels in response to oral glucose load in fructose-fed rats. In summary, both quinapril and diltiazem were able to prevent BP elevation levels in the fructose-fed rat, and reduced the exaggerated response to an oral glucose tolerance test in these animals.