The effects of pulseless perfusion on the distribution of renal cortical blood flow and on renin release.
The effects of pulseless perfusion on the distribution of renal blood flow and on release of renin were studied in anesthetized dogs. The distribution of renal blood flow to four cortical layers was determined with the radioactive microsphere technique during pulsatile control conditions and after one and 2 hours of pulseless perfusion, without significant changes in mean arterial pressure and mean total renal blood flow. Simultaneously, renal vein blood samples were analyzed for renin (radioimmunoassay technique). During pulseless perfusion there was a consistent and progressive redistribution of blood flow toward deeper cortical layers with the outer cortical layer falling from 36.9 to 25.3% p less than 0.001) and the juxtamedullary cortex increasing from 14.5 to 25.4% (p less than 0.001) after 2 hours. In addition, there was a progressive increase in renal venous concentration of renin, which was 20.91 +/- 6.6 ng. per millimeter per hour after 2 hours of pulseless flow compared to 5.06 +/- 1.16 ng. per millimeter per hour during control conditions (p less than 0.05). These changes in cortical blood flow and in release of renin were not observed in sham-operated controls. The results indicate that pulseless flow alone produced both a significant increase in renal production of renin and a significant redistribution of renal cortical blood flow, due to the greater vasoconstriction in the outer cortex when compared to the juxtamedullary cortex.
D000818:Animals; D004285:Dogs; D007672:Kidney Cortex / Q000098:blood supply*; D012039:Regional Blood Flow; D012083:Renin / Q000096:biosynthesis / Q000378:metabolism*
D012083:Renin