Acute beneficial effect of Fluosol-DA on urinary excretion of stroma-free hemoglobin in the isolated rat kidney.

In a timed study over 75 min, divided into 5 15-min periods, experimental perfusions of isolated rat kidneys using Krebs-Ringer bicarbonate (KRB) containing 3.5% (uncrosslinked) stroma-free hemoglobin (SFH) plus 3.5% of the perfluorochemical Fluosol-DA were found to excrete only 13% as much total hemoglobin (Hb) as control perfusions using KRB containing 7% SFH alone (controls). The glomerular filtration rate was the same for experimentals and controls in 3 periods, and slightly higher in the experimentals in 2 periods. However, urine flow was found to be significantly decreased in all 5 periods for the experimentals relative to the controls. These effects can be explained by reabsorption of glomerular filtrate containing Hb by endocytosis of renal tubular cells.