Changes in renal hemodynamics and excretory function induced by a reduction of ANG II effects during renal development

Abstract

The aim was to evaluate whether blockade of ANG II effects during renal development modifies the renal response to an increment of plasma amino acid concentration. It was also examined in anesthetized rats whether the reduction of the renal ability to eliminate an acute volume expansion (VE), elicited by blockade of ANG II during renal development, is sex and/or age dependent. Newborn Sprague-Dawley rats were treated with vehicle or an AT1-receptor antagonist (ARA) during postnatal nephrogenesis. Amino acid infusion induced increments ( P < 0.05) of glomerular filtration rate (31 ± 6%) and renal plasma flow (26 ± 5%) in male but not in female vehicle-treated rats. Natriuretic and diuretic responses to amino acid infusion were similar in male and female vehicle-treated rats. These renal hemodynamics and excretory responses to amino acid infusion were abolished in ARA-treated rats. Renal responses to VE were evaluated at 3–4 and 9–10 mo of age in vehicle and ARA-treated rats. VE-induced natriuresis and diuresis were reduced by more than 38% ( P < 0.05) in 3- to 4-mo-old male and female ARA-treated rats. An age-dependent reduction ( P < 0.05) in the renal ability to eliminate VE was found in male but not in female rats treated with ARA. Our results demonstrate that the renal effects induced by an increment in amino acids are abolished when ANG II effects have been reduced during nephrogenesis. In addition, this reduction of ANG II effects elicits an impairment of the renal ability to eliminate an acute VE in males and females, which is aggravated by age only in male rats.