Tissue plasminogen activator (PA) and urokinase inhibitor in the tissue of neutral and hyperthyroid goitre

The authors found twofold higher activity of the plasminogen activator (PA) in the thyroid tissue of patients with Graves-Basedow disease as compared to the activity in tissue of the hyperthyroid nodular and neutral goitres. This activity mainly depends on the activator of urokinase type which is included in all kinds of goitre in similar amounts i.e. about 90%. The quantitative evaluation of the activity of the urokinase inhibitor points to its marked concentration in the tissue of both hyperthyroid and neutral goitres. Taking into consideration the above data and the higher fibrinolytic activity of the blood serum in the thyroid veins than in the peripheral veins it may be assumed that there is a serious danger of excessive activation of fibrinolysis after a subtotal resection of the thyroid gland.