Does excessive tissue oxygen supply contribute to the development of spontaneous arterial hypertension in rats?

Fifteen spontaneously hypertensive rats of the Okamoto strain and 14 normotensive Wistar rats were kept on low iron diet until 3 weeks old. Nine hypertensive and 10 normotensive rats fed regular diet served as controls. Hypertensive rats exhibited higher haematocrit and haemoglobin levels. Low iron diet produced a more pronounced decrease in the haemoglobin level in hypertensive than in normotensive rats, indicating increased iron turnover in the former group. Anaemia inhibited development of arterial hypertension in Okamoto strain rats whereas it did not affect blood pressure in normotensive rats. The results point to an important role of the blood oxygen carrying capacity for the development of spontaneous hypertension in rats.