Increased vascular endothelin-1 gene expression with unaltered nitric oxide synthase levels in fructose-induced...

The present study aimed to investigate whether altered expression levels of endothelin-1 (ET-1) and nitric oxide synthase (NOS) are related to the development of insulin-resistant hypertension. Male Sprague-Dawley rats were fed a fructose-rich diet for 5 weeks. Systolic blood pressure significantly increased in fructose-fed rats. While serum free fatty acid (FFA) and plasma nitrite/nitrate (NOx) levels did not significantly differ between the fructose-fed and control groups, plasma insulin and serum triglyceride (TG) concentrations significantly increased in the former. ET-1 mRNA expression in the aorta increased to 195% in fructose-fed rats. Neither the protein expression of constitutive NOS (cNOS) nor that of inducible NOS (iNOS) were significantly affected by fructose feeding. However, NOx levels in the aorta were significantly increased. These results indicate that an increased expression of vascular ET-1 may be causally related to the development of hypertension in fructose-fed rats. However, an altered role of the vascular nitric oxide (NO) pathway may not be primarily involved in the development of fructose-induced hypertension.