Angiotensin blood levels in hemorrhagic hypotension and other related conditions

Abstract

Angiotensin blood levels were measured in anesthetized dogs under different experimental conditions. In hemorrhagic hypotension, a marked and progressive increase in angiotensin blood levels was detected. No increase was found when a similar reduction in renal perfusion pressure was elicited by constriction of the aorta above the renal arteries. A high dose of norepinephrine infused simultaneously with the constriction of the aorta produced a significant increase in angiotensin blood levels which was lower than the one detected after hemorrhage. A potentiation of the effect of dog renin injections on angiotensin blood levels by bleeding was shown. It is concluded that the rise in angiotensin blood levels after hemorrhage is not solely due to a decreased renal perfusion pressure. Other possibilities are discussed.