Single‐Nephron Filtration during Hemorrhagic Hypotension in the Conscious Rat

To decide whether redistribution of filtrate between superficial (S) and deep (D) nephrons takes place when GFR is reduced by hemorrhagic hypotension (HH) the amount of filtered ¹⁴C ferrocyanide precipitated as Prussian blue in single S and D nephrons was determined in rats during HH of 80, 65 and 50 mm Hg mean arterial pressure (AP). Marked filtration and urine flow persisted only in the AP 80 mm Hg group, whereas the major fraction of nephrons had ceased filtration in four out of live rats at AP 50 mm Hg. The distribution of radioactivity between S and D proximal tubules was not altered in any of the HH groups as compared to normotensive controls.