Fructose increases blood pressure and activates the brain angiotensin AT1 system

Abstract

In humans there is an association between obesity, diet and cardiovascular disease. The objective of this study was to determine the effect of consumption of liquid fructose on disease related pathologies, particularly as related to blood pressure (BP) and the brain renin angiotensin system (RAS). C57/BL mice were given water (n = 6) or fructose (10%, n = 6) to drink for 30 days. Radiotelemetric probes were implanted for continuous BP monitoring. Food intake (24 hr) was lower in fructose (4.4±1.0 g vs. 2.9±0.4 g; Con vs Fruc) while water intake was more than twice that of controls (5.5±0.3 vs 15.2±1.1 ml/24hr;Con vs Fruc). There was no difference in body weight between groups. Blood glucose was significantly elevated at 30 days (183 mg/dl vs. 212 mg/dl). Mean arterial pressure (MAP) at day 30 of fructose consumption was significantly elevated as compared to controls (110±1mmHg vs. 116±2 mmHg, Con vs Fruc, p<0.05). Brainstem Ang AT1a system was evaluated using in situ hybridization (ISH). Preliminary results indicate that Ang AT1a mRNA was higher in the brainstem nucleus tractus solitarius (NTS) region of the fructose group (0.57±0.03 μCi/g vs. 0.73±0.03 μCi/g, Con vs Fruc, p < 0.05). There was a trend to an increase in the locus coeruleus (0.62±0.03 μCi/g vs. 0.64±0.02 μCi/g). The data show that consumption of fructose and the resultant metabolic changes are associated with increased BP and activation of the brainstem RAS.