Effect of prolonged dietary administration of vanadate on blood pressure in the rat.

Vanadate, a potent naturally occurring Na+,K+-ATPase inhibitor thought to have a role in regulating Na+-K+ pump activity, was fed to uninephrectomized rats drinking tap water or a 1% solution of sodium chloride for as long as 56 weeks. Feeding was achieved by adding sodium orthovanadate to normal rat chow equivalent to 100 or 200 ppm vanadium by weight. In the rats drinking tap water, systolic pressure gradually increased over a period of several weeks and then was sustained in a dose-related manner for the duration of the treatment. The increased pressure was not associated with changes in water intake, urine output, or urinary sodium excretion but correlated positively with plasma vanadium levels ranging from 0.04 to 0.27 microgram/ml. Increased pressure was associated with increased heart-to-body-weight ratio but did not appear to occur in a small group of animals drinking the 1% solution of sodium chloride. These findings, considered in the light of others, indicate that vanadate deserves continued study in relation to hypertension.