Autoregulatory responses of renal plasma flow (RPF) and glomerular filtration rate (GFR) to reductions in renal artery pressure (RAP) were studied in both kidneys of two-kidney, one-clamp dogs and in dogs treated with deoxycorticosterone acetate (DOCA; 25 mg/kg) plus high sodium diets with and without renal arterial clamping. In non-DOCA-treated animals, unilateral renal artery constriction resulted in a significant difference (P = 0.004) in renal renin activity (RRA) between the clamped (171 +/- 37 ng AI.mg-1.h-1) and the contralateral (57 +/- 23 mg AI.mg-1.h-1) kidneys with no change in their relative autoregulatory ability. In dogs treated with DOCA/high sodium there were no differences in RRA between the clamped and contralateral kidneys. The dogs treated with DOCA/high sodium were able to autoregulate both RPF and GFR even though their RRA was only 5.4 ng AI.mg-1.h-1. DOCA/high sodium treatment, however, reduced basal RPF (22%) and GFR (23%) below those in non-DOCA-treated animals. Analysis of the autoregulatory ability of individual kidneys showed no relationship to either RRA or renin secretory rates. These results support the conclusion that the renin-angiotensin system is not necessary component in the autoregulation of RPF or GFR.