Effect of gold sodium thiomalate on fibrinolysis

Effects of gold sodium thiomalate (GST) on fibrinolytic activities of normal blood and plasma, polymorphonuclear leukocytes (PMN), purified PMN fibrinolytic enzymes, and the enzyme, plasmin, were examined by 125I-fibrin radiometric assay. Of the 2 enzymes accounting for all of the fibrinolytic activity extractable from PMN, the chymotrypsin-like enzyme (cathepsin G),but not the elastase, was inhibited by GST (50% inhibition at 10-6M, 80% inhibition at 10-5M). Plasmin was not inhibited by GST (10-4M to 10-7 M), and these concentrations had no effect on fibrinolytic activities of normal blood and plasma (6 subjects). Activities of PMN preparations from only 2 of 5 normal subjects were inhibited by GST (maximum inhibition of 29% at 10-5 M). These findings indicate a differential effect of GST on PMN elastase and cathepsin G, and suggest a minor role for the latter in normal PMN fibrinolytic activity.