The present study evaluates the participation of oxidative stress, tissue angiotensin II (Ang II) and endothelin (ET) in the effects of losartan on blood pressure (BP), ventricular hypertrophy and renal injury in spontaneously hypertensive rats (SHRs), and explores how these effects are modified when spontaneous hypertension is transformed in a low-renin model by the administration of deoxycorticosterone acetate (DOCA). The following groups were used: SHR-control, SHR+DOCA, SHR+losartan and SHR+DOCA+losartan. Tail systolic BP was measured once a week. After 9 weeks of treatment, direct BP and metabolic, morphological, biochemical and renal variables were measured. DOCA administration to SHRs produced an increase in BP, ventricular hypertrophy, renal weight, proteinuria, renal histopathological lesions, urinary excretion of isoprostane F2α and ET levels in the renal cortex. Losartan reduced BP, plasma malondialdehyde levels, urinary excretion of isoprostane F2α, renal Ang II and renal and urinary levels of ET in the SHR and DOCA-treated SHR groups. Losartan increased plasma nitrite/nitrate in SHRs, but not in low-renin DOCA-treated SHRs. Losartan reduced ventricular hypertrophy and ventricular Ang II in SHRs, but not in DOCA-treated SHRs. Losartan significantly decreased proteinuria and renal injury in DOCA-treated SHRs. We conclude that (i) the DOCA-induced aggravation of hypertension, ventricular hypertrophy and renal injury in SHRs is accompanied by augmented oxidative stress and increased levels of ET in the renal cortex, which could contribute to their development; and (ii) losartan reduced oxidative stress and renal Ang II and ET in SHRs and DOCA-treated SHRs, which might contribute to its antihypertensive and renoprotective effects, regardless of renin status.
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March 2004
Research Article|
March 01 2004
Protective effects of the angiotensin II type I (ATI) receptor blockade in low-renin deoxycorticosterone acetate (DOCA)-treated spontaneously hypertensive rats
Virginia CHAMORRO;
Virginia CHAMORRO
*Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain
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Rosemary WANGENSTEEN;
Rosemary WANGENSTEEN
*Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain
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Juan SAINZ;
Juan SAINZ
*Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain
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Juan DUARTE;
Juan DUARTE
†Departamento de Farmacología, Facultad de Farmacia, Universidad de Granada, Granada, Spain
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Francisco O'VALLE;
Francisco O'VALLE
‡Departamento de Anatomía Patológica, Facultad de Medicina, Universidad de Granada, Granada, Spain
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Antonio OSUNA;
Antonio OSUNA
§Unidad Experimental, Servicio de Nefrología, Hospital Universitario Virgen de las Nieves, Universidad de Granada, Granada, Spain
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Félix VARGAS
*Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, Granada, Spain
Correspondence: Dr F. Vargas (e-mail fvargas@ugr.es).
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Clin Sci (Lond) (2004) 106 (3): 251–259.
Article history
Received:
September 09 2003
Accepted:
October 02 2003
Accepted Manuscript online:
October 02 2003
Citation
Virginia CHAMORRO, Rosemary WANGENSTEEN, Juan SAINZ, Juan DUARTE, Francisco O'VALLE, Antonio OSUNA, Félix VARGAS; Protective effects of the angiotensin II type I (ATI) receptor blockade in low-renin deoxycorticosterone acetate (DOCA)-treated spontaneously hypertensive rats. Clin Sci (Lond) 1 March 2004; 106 (3): 251–259. doi: https://doi.org/10.1042/CS20030299
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