Chronic one-kidney hypertension in rabbits. III. Renopressin, a new hypertensive substance.

The blood pressure of rabbits with chronic one-kidney hypertension can be lowered to normal by immunization with hog kidney cortex preparations that do not contain renin, thus providing evidence for a new factor essential for the maintenance of an elevated blood pressure. A search for the new factor has led to the discovery of a hypertensive substance which we have named renopressin. Subcutaneous injection of the new substance into normal rabbits produces a delayed, slow increase in blood pressure, and after a few days the development of a moderate hypertension which persists indefinitely. The response of the blood pressure to renopressin is totally unlike that to renin. While the pressor action of renin can be blocked by an angiotensin II antagonist, the hypertension caused by renopressin cannot. Renin can increase the blood pressure of hypertensive rabbits; renopressin has no effect. The blood pressure of hypertensive rabbits and of normal rabbits made hypertensive by injection of renopressin can be lowered to normal by passive immunization with the same antibody preparation. The evidence is consistent with the possibility that renopressin and the agent causing the elevation of blood pressure in hypertensive rabbits are similar or identical.