Intrarenal Hemodynamics in Nonfiltering, Filtering, and Compensated Kidneys

Renal blood flow and intrarenal blood flow distribution were studied in nine nonfiltering and contralateral compensated kidneys and in seven control filtering kidneys. Unilateral ureteral ligation coupled with a 2-hr renal ischemia 4 days prior to the experiment induced the kidney to be nonfiltering and resulted in a marked decrease in renal blood flow (59.2 ± 35.1 ml/min vs 124.7 ± 12.9 ml/min in control, P < 0.05). In contrast, the contralateral kidney demonstrated a compensatory increase in renal blood flow (48%) equal to the reduction in flow to the impaired kidney (52%). Regional blood flows to the four cortical zones were commensurate with the rise in total flow in that they increased markedly in all zones of contralateral kidneys. In nonfiltering kidneys, the decrease in total flow was due to a proportional fall in regional blood flows of zones I, II, and III. Blood flow in zone IV also decreased but not to the extent seen in the other zones. Thus, it may be concluded that the large changes in renal hemodynamics to nonfiltering and compensated kidneys are proportionally distributed throughout the four cortical zones with the exception of an attenuated decrease in blood flow in the innermost zone.