Effect of Hemorrhage on Arterial Plasma Renin Activity in the Rabbit

Arterial plasma renin activity in the rabbit was measured at the beginning and end of a brisk hemorrhage and 40 min later. Activity rose to a mean of two and one-half times the control value during the hemorrhage, and was five times greater than the control 40 min later. The rise in plasma renin activity was not due to anesthesia, as light pentobarbitone produced no change. Conscious rabbits, severely bled from a carotid cannula, 2 to 5 hr after an ether anesthetic, also showed an increase in plasma renin activity at the end of hemorrhage. Forty-eight hours after both kidneys had been removed, renin activity was virtually absent and did not rise after hemorrhage.