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) le vels in normal rats, which is associated with insulin resistance, hype rinsulinemia, and hypertriglyceridemia. Increased vascular resistances in skeletal muscle have been proposed to contribute to BP elevation a nd insulin resistance in this animal model. To further explore the mec hanisms underlying the fructose-induced hypertension in rats, the effe cts of quinapril and diltiazem on BP, renal function, plasma levels of glucose, insulin, and triglycerides, and insulin resistance were stud ied. Male Sprague-Dawley rats were fed for 4 weeks with diets containi ng 60% fructose or 60% starch and received quinapril or diltiazem in t he drinking water. Fructose-fed rats showed higher BP and plasma level s of insulin and triglycerides when compared to controls. Treatments w ith quinapril or diltiazem prevented BP elevation and reduced elevated plasma insulin levels in fructose-fed rats. Plasma glucose and insuli n 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 qu inapril or diltiazem prevented the exaggerated plasma insulin and gluc ose levels in response to oral glucose load in fructose-fed rats. In s ummary, 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.