THYROID HORMONAL AXIS MODULATES FIBRINOLYSIS IN THE RAT. EFFECTS OF TRH, TSH, T3 AND T4 ON FIBRINOGEN, FDP, D-DIMER AND REPTILASE TIME

Thyroid disorders are often reported to be accompanied by modulation of hemostasis. However, the precise role of the hormones of the thyroid hormonal axis in this aspect is not completely established yet. This study was aimed to investigate the effects of thyrotropin releasing hormone (TRH), thyroid-stimulating hormone (TSH), triiodthyronine (T3), and tyroxine (T4) on blood fibrinogen, fibrin degradation products (FDP), D-dimer, and reptilase time in rats. The experiments were performed on 65 male Wistar rats. Fibrinogen and reptilase time were determined by standard kinetic methods; FDP and D-dimer - by ELISA methods. Fibrinogen plasma concentration was reduced; FDP and D-dimer were elevated; reptilase time was significantly elongated (p < 0.001) in all experimental groups by all the hormones applied. The reptilase One, fibrin degradation products and D-dimer, important parameters characterizing the functional status of the fibrinolytic system, are shifted unidirectionally and complementary by the hormones enrolled in this study. This allows the presumption that the hormones of hypothalamic-pituitary-thyroid axis (TRH, TSH, T3, and T4) modulate plasma fibrinolytic activity in rats via activation of fibrinolytic system.