Urinary excretion of angiotensinogen in male and female Sprague Dawley rats during angiotensin II infusion and high salt diet

Abstract

We have found that urinary angiotensinogen (AGT) excretion (uAGT) differs between male(♂)and female(♀) Sprague Dawley (SD) rats on a normal salt diet (♂: 60±26 vs ♀: 4.5 ±0.2ng/day, p<0.05). In this study, we examined if the effects of a high salt (HS) diet on uAGT exhibits sexual dimorphism during Angiotensin (ANG) II dependent hypertension. Four groups of age‐matched (8 weeks) male (n= 20) and female (n=17) SD rats were studied: 1) high salt diet (HS; 8%NaCl); 2) ANG II (80ng/min, sc; for 14 days); 3) ANG II + HS; 4) ANG II + HS + Candesartan. (CAND, 25 mg/L in drinking water). uAGT levels were measured by enzyme immunoassay. HS diet alone did not raise uAGT levels (♂: 107±23 vs. ♀: 5±2ng/day) from baseline; however, AGT increased significantly during ANG II infusion (♂: 1107±1061 vs ♀: 206±74ng/day, p<0.01) and was augmented even further in ANG II + HS (♂: 4363±1673 vs. ♀: 8022±1300ng/day, p=ns). Candesartan ameliorated this effect with a better response in female than in male rats.(♂: 240±28 vs. ♀: 10±4 ng/day, p< 0.01). The results demonstrate a sexual dimorphism in the uAGT excretion rate during baseline conditions and HS diet characterized by higher levels in the males. The augmentation of uAGT with HS + ANG II is ameliorated more effectively by ARB treatment in female ANG II hypertensive rats than in males.NIH (P20 RR 017659), Tulane‐BIRCWH (K12HD043451)