Role of angiotensin II in autoregulation of GFR

Effect of reducing renal artery pressure (from a baseline value of approximately 125 mmHg) on glomerular filtration rate (GFR), expressed as a percentage of control values in dogs fed a normal sodium diet. The blue squares represent control animals in which both GFR was maintained until the pressure was markedly reduced. The red circles represent animals given an intrarenal infusion of an angiotensin II antagonist; autoregulation of GFR was less well regulated. Although not shown, autoregulation also applies to GFR when the renal artery pressure is initially raised and to renal blood flow, which is not impaired by inhibiting the activity of angiotensin II.