ANTIHYPERTENSIVE EFFECT OF ORAL NITRITE UPTAKE IN THE SPONTANEOUSLY HYPERTENSIVE RAT

The lower blood pressure of vegetarians might partly, be due to the high dietary, load with nitrate which - to a certain extent - is further reduced to nitrite and finally to nitric oxide. To test this hypothesis, spontaneously hypertensive rats received drinking water containing 0, 25, 50 or 100 mmol/l NO2 during 56 days. Food was offered ad libitum or was restricted by 20 % (pair-feeding) to simulate the lower energy consumption of vegetarians. Blood pressure, which was monitored at regular intervals, was lowered in a dose-dependent manner by nitrite. This effect was reversible and could not be enhanced by energy restriction. In volunteers plasma nitrate levels increased by a factor of 8 to 32 following the ingestion of a nitrate-rich meal, and mean methemoglobin concentrations increased from 1.2 % to 2.4 % indicating the endogenous formation of nirite under these conditions.