Ang II releases renal cyclic GMP (cGMP) by AT2R activation. Renal interstitial fluid cGMP levels in response to intravenous infusion of Ang II; Losartan, an AT1R antagonist; PD, PD-123319, an AT2R antagonist, and combinations in Sprague-Dawley rats. Control vehicle infusion data, white bars; experimental agent infusion, black bars. Data represent mean ± 1 SE. * P<0.001 from vehicle or time control; + P<0.001 from Ang II alone. Adapted from Siragy *HM and Carey RM. J Clin Invest. 1996;97:1978–1982 and Siragy HM and Carey RM. J Clin Invest. 1997:100:264–269 with permission.