ABSTRACT
Tissue-type plasminogen activator (t-PA) is cleared very rapidly from the circulation by the liver, its circulatory half-life ranging from 1 to 4 min, depending upon the size of the organism. The observation that transgenic animals deficient in t-PA show reduced thrombolysis has again highlighted the essential role of t-PA in the fibrinolytic/thrombolytic system in the blood. Clinical studies on the release of t-PA are performed to determine whether the reactivity of a patient’s fibrinolytic system is normal, or in any way deficient. In general outline, these studies involve stimulation of the patient’s release system, followed by the determination of the plasma concentration of t-PA antigen. The vasopressin analogue deamino-D-arginine vasopressin, originally developed as an analogue that mimicked vasopressin’s antidiuretic effect without its vasoactive side effects, was subsequently shown also to increase plasma levels of Von Willebrand factor, coagulation factor VTA, and t-PA.
