Effects of angiotensin II on the renal antioxidant activities of borderline hypertensive rats

This study was aimed to study the angiotensin II (Ang II)-induced antioxida nt changes in the kidney of borderline-hypertensive rats (BHR). We measured renal antioxidant enzyme activities, and glutathione (GSH) contents and li pid peroxide levels in relation to the age of subjects. In the antioxidant enzyme assays, consistent changes were not observed in relation to age. How ever, in the assay for reduced GSH, nonenzymatic antioxidant, contents of a dult and aged rats were much greater than those of weanling rats. Subcutane ous injection of pressor dose of human Ang II (200 mug/kg over 90 min) sign ificantly reduced enzymatic activities in the weanling (4-week-aged) and ad ult (10-week-aged) BHR. However, in the relatively aged (16-week-aged) rats , Ang II did not alter enzymatic activities. Renal GSH contents of aged BHR , were highly increased by Ang II. Renal lipid peroxide levels of weanling and adult BHR were increased by Ang II, but decreased in the aged rats. How ever, these characteristic changes of renal antioxidant due to Ang II of th e BHR could not be observed in the age-matched control, Wistar-Kyoto rats ( WKR). From these results, it can be concluded that impacts of oxidative str ess on the kidney of BHR may be greater in the young rats. Copyright (C) 20 01 S. Karger AG, Basel.