Thromb Haemost 1983; 50(02): 518-523
DOI: 10.1055/s-0038-1665244
Original Article
Schattauer GmbH Stuttgart

Behaviour and Quantitation of Extrinsic (Tissue-Type) Plasminogen Activator in Human Blood

C Kluft
The Gaubius Institute, Division of Health Research TNO, Leiden, The Netherlands
,
A F H Jie
The Gaubius Institute, Division of Health Research TNO, Leiden, The Netherlands
,
R A Allen
The Gaubius Institute, Division of Health Research TNO, Leiden, The Netherlands
› Institutsangaben
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Publikationsverlauf

Received 30. September 1982

Accepted 10. Mai 1983

Publikationsdatum:
18. Juli 2018 (online)

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Summary

Functional assay of extrinsic (tissue-type) plasminogen activator (EPA) in plasma on fibrin plates was evaluated. Using specific quenching antibodies, we demonstrated the method to be specific for EPA under all conditions tested. Contributions of urokinases and intrinsic activators were excluded. The quantity of EPA in blood samples, as compared with purified uterine tissue activator, shows 1 blood activator unit (BAU) to be comparable to 0.93 ng.

The median values for EPA activity for healthy volunteers were: baseline, 1.9 BAU/ml (n = 123); diurnal, 5.5 BAU/ml (n = 12); DDAVP administration, 11.7 BAU/ml (n = 39); exhaustive exercise, 25 BAU/ml (n = 24); venous occlusion (15 min), 35 BAU/ml (n = 61). A large inter-individual variation in EPA activity was found, while individual baseline values tended to be constant for periods of weeks.

In vitro in blood EPA activity shows a disappearance of 50% in about 90 min at 37° C; EPA activity in euglobulin fractions is stable for ≤2 hr at 37° C.

A rapid decrease in EPA activity occurs in vivo, as noted after extracorporal circulation and exercise stimulation (t½ decay, 2-5 min).