Summary
Molecular exclusion chromatography was performed on samples of urine from normal and
aminonucleoside nephrotic rats. Normal urine contained 2 peaks of urokinase activity,
one having a molecular weight of 22,000 and the other around 200,000. Nephrotic urine
contained three peaks of activity with MW’s 126,000, 60,000 and 30,000. Plasma activator
determined from euglobulin precipitate had a MW. in excess of 200,000. The results
indicate that in the normal animal, plasma plasminogen activator does not escape into
the urine in substantial quantities but under the conditions of extreme proteinuria
there may be some loss through the kidney. The alteration in urokinase output in nephrotic
animals indicates a greatly disordered renal fibrinolytic enzyme system.
The findings of this study largely support the hypothesis that plasma plasminogen
activator of renal origin and urinary plasminogen activator (urokinase) are different
molecular species.
