Haemostatic disturbances are observed in thyroid diseases. The fibrinolytic system reaction is suspected to be the cause. There are few data about the nature of fibrinolytic changes in the serum of patients suffering from Graves disease. The aim of our work was to study serum fibrinolytic system changes in Graves disease due to the concentration of plasminogen activators type of tissue (t-PA) and urokinase (u-PA) and plasminogen activator inhibitor type 1 (PAI-1). The study was performed on 33 patients (F/M 29/4, mean aged 35.0 years) with Graves disease and on 34 healthy volunteers(F/M 28/6, mean age: 33.7 years). Graves disease was diagnosed on the basis of clinical and laboratory evidence of thyrotoxicosis, diffuse goitre and absence of other symptoms of thyrotoxicosis. In the citric blood plasma the concentrations of tissue (t-PA) and urokinase (u-PA) plasminogen activators, and plasminogen activator inhibitor type 1 (PAI-1) antigen were determined using ELISA - test (Biopol, Sweden). The individual values of t-PA Ag and PAI-1 Ag in patients with Graves disease were ranged much wider than in control group and the concentration of antigens reached the highest values in several
cases. Mean concentrations of t-PA, u-PA and PAI-1 antigen in blood plasma of patients were significantly increased comparing to the control group. The hyperthyroid goitre in patients suffering from Graves disease seems to be the source of plasminogen activators (t-PA, u-PA) detected in the blood plasma.

Keywords: Graves Disease, fibrinolitic system, Plasminogen Activators, inhibitors