Fructose loading induces cardiovascular and metabolic changes in nondiabetic and diabetic rats

The effects of fructose loading on the integrated cardiovascular function in vivo, glycemic control, glucose tolerance, and plasma lipid levels in nondiabetic and streptozotocin (STZ) diabetic rats were investigated. Endothelial morphology of the thoracic aorta was also assessed with scanning electron microscopy. Fructose-loaded nondiabetic rats exhibited 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 greater increase in plasma insulin in response to glucose challenge in these animals than in the control. Compared with the untreated STZ-diabetic animals, fructose-loaded diabetic rats had significantly greater hyperglycemia, glucose intolerance, and hyperlipidemia and higher blood pressure, but had a similar degree of hypoinsulinemia, cardiac dysfunction, and cardiac enlargement. They also showed signs of early atherogenesis. The central venous pressure and the susceptibilities of the rats to the induction of ventricular arrhythmias by intravenous infusion of aconitine were not significantly affected by either STZ injection or fructose loading. It is concluded that prolonged intake of an excessive amount of fructose has detrimental effects on the cardiovascular system, glucose metabolism, and plasma lipid levels in both nondiabetic and STZ-diabetic rats.