Role of vascular wall renin: intracellular and extracellular mechanism.

Inhibitors of angiotensin-converting enzyme, renin and angiotensin II receptor lower the blood pressure of spontaneously hypertensive rats (SHRs) used as a model of essential hypertension. Since their plasma renin levels were normal or subnormal, renin in the vascular tissue was considered to play a key role in the maintenance of the hypertension. To clarify the source and localization of vascular renin in SHRs, the effects on blood pressure of antirenin antibodies, the converting enzyme inhibitors delapril and enalapril, and the angiotensin II receptor antagonist DuP 753 were examined in intact and bilaterally nephrectomized SHRs and their normotensive controls. The efficient hypotensive action of the renin antibody indicated that renin of the renal origin is a dominant factor. The gradual but complete disappearance of the antihypertensive action of these inhibitors of the renin-angiotensin system upon bilateral nephrectomy indicated the importance of membrane-associated renin of the renal origin and angiotensin-converting enzyme in the maintenance of the spontaneous hypertension.