Effect of sodium molybdate on fructose-induced hyperinsulinemia and hypertension in rats

Aim: Insulin resistance, hyperinsulinemia, hypertriglyceridemia and hypertension occur in rats fed with high fructose diet. On the other hand, sodium molybdate (Mo) has insulin-like effects in animal models of type I and type II diabetes. The aim of this study was to examine the effects of Mo on fructose-hypertensive rats. Material and methods: Male Wistar rats were divided into four experimental groups: control (C), control treated with molybdate (CT), fructose (F), fructose treated with molybdate (FT). CT and FT groups received Mo at increasing concentrations in food and in drinking water. F and FT groups were given a 10% fructose solution (15% after 15 weeks) to drink ad libitum during experimental period. Systolic blood pressure (SBP) and plasma glucose, insulin, triglyceride levels of rats were measured weekly. Results: SBP and glucose, insulin, and triglyceride levels in F group were significantly higher than in C group throughout the study. Mo treatment completely prevented fructose-induced hyperglycemia, hyperinsulinemia and hypertension, whereas it has partially suppressed the increased triglyceride levels. The biochemical parameters and SBP were not significantly different between C and CT groups. Insulin sensitivity of F group was decreased when compared to C group, whereas there was no change in FT group. At last, oral glucose tolerance test (OGTT) was performed in all groups. During the OGTT, glucose and insulin levels in F group were significantly higher than those in C, CT and FT groups. On the other hand, we found that there was a positive correlation between plasma insulin concentrations and SBP in F and FT groups. Conclusion: Our results have shown that insulin resistance and/or hyperinsulinemia is responsible for hypertension and that molybdate treatment prevented fructose-induced hyperinsulinemia and hypertension in rats.