High-fructose Diet Does Not Raise 24-hour Mean Arterial Pressure in Rats

High intakes of the simple sugars--glucose, sucrose, and fructose--have been reported to raise significantly systolic pressure in rats. It is not clear, however, if under those conditions the acute measurement of blood pressure, especially with the tail-cuff technique, represents accurately the effect of the diet on mean arterial pressure throughout the day. In this study, 15 Sprague-Dawley rats (approximately 325 g) were chronically instrumented with arterial and venous catheters and placed on a diet containing 61% vegetable starch and 5% dextrose; seven rats remained on this diet throughout the study. After 4 days of control measurements, eight rats were switched to a diet that substituted 66% fructose for the vegetable starch and dextrose. Mean arterial pressure (MAP) was measured 20 h/day by computerized methods. MAP during the 4 control days averaged 100 +/- 3 and 105 +/- 3 mm Hg in low-fructose (LF) and high-fructose (HF) diet rats, respectively. Switching to the HF diet caused no change in MAP, and after 11 days MAP averaged 104 +/- 2 and 108 +/- 3 mm Hg in the LF and HF rats, respectively. In addition, the variability of MAP over the 20-h period each day was not altered by the HF diet, and raising sodium intake fourfold caused a similar rise in MAP in both groups. There also were no significant changes in plasma glucose or insulin concentrations. Thus, a change in dietary simple sugar content from 5% dextrose to 66% fructose did not change MAP or alter blood pressure variability or sodium sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)