Renal function following branch-artery ligation in the canine kidney.

Viable kidney mass has been reduced in dogs by branch-artery ligation combined with uninephrectomy. 1. When viable kidney remnants amount to about 1/4 of the original kidney mass dogs survive in apparent good health with moderate azotaemia; with 1/8 to 1/10 kidney remnants azotaemia is progressive and uraemic death supervenes within some days. 2. Reduction of renal blood flow and of glomerular filtration rate to about one-fourth of their respective control values seems to be compatible with survival; with further reduction death ensues. An inverse and linear relationship between NPN and GFR on a log-log basis has been found. 3. Mean nephron blood flow is equally enhanced in both the more and the less severely infarcted kidneys. On the other hand, mean nephron glomerular filtration is increased when about one half of the kidney is viable, but decreased with more extensive infarction. 4. Mean nephron vascular resistance is diminished; considering the pronounced decrease in Ein, i.e. filtration fraction, predominance of postglomerular vasodilatation is assumed. The formation of non-filtering, actively perfused nephrons is taken into consideration.