Effects of Intravenous Fructose Infusion on Sodium Handling and Peripheral Vascular Tone in Pre-Hypertensive Subjects.

The hemodynamic and humoral effects of i.v. fructose infusion and a control infusion were studied in 12 borderline hypertensive patients according to a single-blind, cross-over, randomized protocol. Fructose infusion decreased urinary sodium excretion and significantly increased plasma insulin, plasma Na+/K+ ATPase inhibitory activity, and forearm arterial and venous tone (+13%), the last of which was not observed during the control infusion (-2.5%). Levels of ANF and PRA in plasma were not altered by either infusion. We conclude that the sodium retention caused by acute i.v. fructose loading could be related to the increase in plasma insulin levels, which may directly affect individual susceptibility to sodium by enhancing sodium reabsorption at renal tubules. This sodium retention could contribute to the release of a plasma Na+-pump inhibitor apparently unrelated to extracellular volume expansion and potentially responsible for the early peripheral vascular involvement found in hypertension-prone men. (Hypertens Res 1994; 17: 239-242)