Objectives: 

Previous studies have proposed that angiotensin II (Ang II) effects are modulated by sex hormones. However, it remains to be investigated whether the renal hemodynamic effects of Ang II are sex-dependent at different ages. The main objective of this study was to evaluate whether the renal hemodynamic effects of Ang II are sex- and ageing-dependent, and to examine whether these renal effects can be explained by differences in renal AT1 receptor expression and/or in oxidative stress.

Materials: 

The renal hemodynamic response to exogenous Ang II administration (30ng/kg/min), renal AT1 receptor expression and oxidated protein levels in renal tissue were examined in male and female rats at 3-4 and 9-11 months of age.

Results: 

The decrease in renal blood flow and glomerular filtration rate elicited by Ang II was similar in male and female rats at 3-4 months of age. The Ang II-induced increment in renal vascular resistance (RVR) was not significantly different in male (7,7 +/­ 0,9 mmHg/ml/min) and female (11,4 +/­ 1,9 mmHg/ml/min) rats. Renal AT1 receptor expression was also similar in both sexes at 3-4 months of age. The renal hemodynamic response to Ang II did not change significantly between 3-4 and 9-11 months of age in male and female rats. The increment in RVR was also similar in male (13,8 +/­ 3,0 mmHg/ml/min) and female (10,8 +/­ 1,3 mmHg/ml/min) rats at 9-11 months of age. Renal oxidated protein levels were similar in both sexes at that age. However, the renal AT1 receptor expression increases (P<0.05) with age in male but not in female rats.

Conclusions: 

The results of this study present new evidence demonstrating that the renal hemodynamic effects of Ang II are similar in both sexes of normotensive rats, despite renal AT1 receptor expression only increases with age in male rats.