title: Renal calculi-urate as a urokinase inhibitor.
abstract: The formation of renal calculi is one of the most widely studied urinary ailments. Spectrophotometric analysis of urinary inhibition on the urokinase/plasmin system revealed a significant difference between subjects with and without renal calculi (P less than 0.001). The percentage urokinase/plasmin inhibition in the two groups was 77.1% for those with, and 47.1% for those without renal calculi. Because of the significant (P less than 0.015) positive correlation (r = 0.762) between the percentage inhibition of urokinase/plasmin and urinary urate concentration, the inhibition of urate on urokinase/plasmin and on plasmin and urokinase was investigated. The urokinase/plasmin system was inhibited up to 94.4% with 0.5 mM urate. Inhibition occurred with both low and high molecular weight urokinases. In order to determine which enzyme of the complex was inhibited, each was investigated independently and a 50% inhibition of urokinase activity was obtained with 4 mM urate. It was found that the urine of stone formers contained a higher concentration of urate than the urine of healthy subjects and that at the same time there was a decrease in urinary urokinase activity in these patients.
authors.affiliation: Department of Urology, H.F. Verwoerd Hospital, University of Pretoria, Republic of South Africa.
authors.forename: C H
authors.initials: CH
authors.lastname: van Aswegen
authors.forename: A W
authors.initials: AW
authors.lastname: Neitz
authors.forename: P J
authors.initials: PJ
authors.lastname: Becker
authors.forename: D J
authors.initials: DJ
authors.lastname: du Plessis
mesh_terms: D000328:Adult; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007669:Kidney Calculi / Q000032:analysis*; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D014527:Uric Acid / Q000032:analysis*; D014568:Urokinase-Type Plasminogen Activator / Q000037:antagonists & inhibitors*
chemical_list: D014527:Uric Acid; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator