The effects of synthetic Angiotensin II on erythropoiesis were investigated.
1. Two daily intravenous injections of Angiotensin II, 100 µg./Kg. of body weight, revealed no acceleration of Fe59 incorporation into erythrocytes of either normal rabbits or hypophysectomized rats.
2. When given by intravenous drip, 100 µg./Kg. of Angiotensin II significantly accelerated the radioiron incorporation.
3. The renal blood flow was markedly reduced throughout the period of the dropwise injection; the same effect was transitory after single intravenous injection. The elevation of plasma erythropoietin activity was observed in hypertransfused polycythemic rabbits following the dropwise injection of Angiotensin II.
From these results, it is concluded that erythropoietic activity of Angiotensin II results from an increased erythropoietin production. The increased production may have been induced by a renal ischemia through administration of Angiotensin II.