Plasminogen activator content of neoplastic and benign human prostate tissues; fibrin augmentation of an activator activity

Abstract

The plasminogen activator content of the extracts of excised prostate cancers (25 specimens) was determined with an azocasein assay and found to be on the average 1.7 times higher than that of extracts of excised prostate benign hyperplasias (29 specimens). Both groups contained the same average percentage of human urokinase type activator (∼45%) as determined by the inhibition of activity when anti‐human urokinase antibody was included in the assay system. The two types of activators were partially purified and found to have distinctly different properties. The most striking difference was the large augmentation of activity of the non‐urokinase enzyme in fibrinolysis. The implications of an enhanced fibrinolysis relative to azocaseinolysis (or other) is discussed, particularly with respect to its importance in the quantitation and characterization of activators by different investigators. Highly purified urokinase‐like activator was found to be similar to commercial urokinase preparation with respect to molecular weight, isoelectric point, inhibition by the antibody, and inhibition by placenta inhibitor.