Resistance to mineralocorticoid-induced hypertensive vascular disease

To support our contention that the Wistar-Furth rat is resistant to mineralocorticoid hypertension, we assessed the effects of deoxycorticosterone (DOC) administered or renal artery stenosis on the development of hypertension in the Sprague-Dawley and Wistar-Furth rat strains. Weekly administration of mineralocorticoid in the form of DOC pivalate resulted in rapid, severe hypertensive cardiovascular disease in Sprague-Dawley rats. Within 5 weeks the mean conscious systolic blood pressures in steroid-treated and control rats were 186 ± 4 and 118 ± 5 mm Hg, respectively. In contrast, blood pressures of Wistar-Furth rats were only moderately elevated, even after 10 weeks of DOC pivalate administration (136 ± 2 vs 116 ± 2 mm Hg for controls. Furthermore, none of the steroid-treated Wistar-Furth animals exhibited cardiovascular lesions. In parallel studies, littermates of these rat strains were subjected to renal artery stenosis and blood pressures were determined weekly in conscious rats. Silver clip constriction of the left renal artery, in the presence of the contralateral kidney, resulted in a rapid, sustained elevation of blood pressure in both Sprague-Dawley and Wistar-Furth rat strains (177 ± 4 and 176 ± 5 mm Hg, respectively). Corticosteroid levels were also determined in DOC-treated Sprague-Dawley and Wistar-Furth rats. The regimen employed resulted in a 10-fold increase in DOC levels as compared with controls, and the levels achieved were comparable in both strains. Thus, the Wistar-Furth rat appears to be selectively resistant to mineralocorticoid hypertensive vascular disease and thus affords a model for studying mechanisms of steroid hypertension.