angiotensin 1-7 administration increases renal blood flow in the absence of bradykinin b2 receptor in ovariectomized estradiol treated rats: the role of mas receptor

Renin angiotensin (ras), kallikrein kinin (kks), and sex hormonal systems demonstrate a complex contribution in kidney circulation. this study was designed to investigate the role of angiotensin 1-7 (ang 1-7) receptor (masr) and of bradykinin b2 receptor (b2r) in renal blood flow (rbf) response to ang 1-7 infusion in ovariectomized estradiol treated rats. the ovariectomized rats received intramuscular vehicle (group 1, ov) or estradiol valerate (500 μg/kg/week) (group 2, ove) for two weeks. then each group was divided into two subgroups subjected to receive b2r antagonist (hoe-140, subgroup a), or masr antagonist (a779) plus hoe-140 (subgroup b). rbf and renal vascular resistance (rvr) responses to graded ang 1-7 infusion were determined. in condition of b2r alone blocking, rbf response to ang 1-7 in ove group was significantly greater than that of ov group (p=0.05), however this response difference was failed by co-blockades of masr and b2r. estradiol could promote rbf response to graded ang 1-7 infusion in the absence of b2r alone, however when both receptors (masr and b2r) were blocked the role of estradiol was limited.