Disorders in the release of plasminogen activators

Impairment of the release of plasminogen activator has been looked for in patients with a predisposition to vascular disease or venous thrombosis. In normal people the fibrinolytic activity of the blood rises sharply after strenuous physical exercise or after the administration of certain drugs, among which DDAVP. These measures fail to elicit a normal response in many of these patients. In most cases this turned out to be due to a high level of a circulating plasminogen activator inhibitor which suppresses the rise in fibrinolytic activity. Release of activator can only be demonstrated reliably by the assay of t-PA-antigen. An impaired release appears to be very rare and in the experience of the author it occurs with some regularity only in patients with terminal renal insufficiency.