FRUCTOSE LOADING INDUCES CARDIOVASCULAR AND METABOLIC CHANGES IN NONDIABETIC AND DIABETIC RATS

The effects of fructose loading on the integrated cardiovascular funct ion in vivo, glycemic control, glucose tolerance, and plasma lipid lev els in nondiabetic and streptozotocin (STZ) diabetic rats were investi gated. Endothelial morphology of the thoracic aorta was also assessed with scanning electron microscopy. Fructose-loaded nondiabetic rats ex hibited elevated blood pressure and pulse rate, and signs of arterial atherogenesis, such as focal adherence of leukocytes and fibrin to the endothelium. Intraperitoneal glucose tolerance tests revealed a great er increase in plasma insulin in response to glucose challenge in thes e animals than in the control. Compared with the untreated STZ-diabeti c animals, fructose-loaded diabetic rats had significantly greater hyp erglycemia, glucose intolerance, and hyperlipidemia and higher blood p ressure, but had a similar degree of hypoinsulinemia, cardiac dysfunct ion, and cardiac enlargement. They also showed signs of early atheroge nesis. The central venous pressure and the susceptibilities of the rat s to the induction of ventricular arrhythmias by intravenous infusion of aconitine were not significantly affected by either STZ injection o r fructose loading. It is concluded that prolonged intake of an excess ive amount of fructose has detrimental effects on the cardiovascular s ystem, glucose metabolism, and plasma lipid levels in both nondiabetic and STZ-diabetic rats.