Description: Chronic treatment of saline-drinking stroke-prone spontaneously hypertensive rats (SHRSP) with agents that interfere with the formation or actions of angiotensin II (Ang II) prevents the development of stroke and renal vascular damage. In both studies, histopathologic examination revealed a marked protective effect of spironolactone against the development of malignant nephrosclerotic and cerebrovascular lesions. These observations indicate a vascular and end organ protective effect of spironolactone in the absence of lowered blood pressure in saline-drinking SHRSP and are consistent with a major role for mineralocorticoids as hormonal mediators of vascular injury.