EXPERIMENTAL-STUDY OF THE EFFECTS OF THYR OTROPIN AND THYROTROPIN-RELEASING-HORMONE ON THROMBOCYTOPOIESIS AND PLASMA THROMBOPOIETIN ACTIVITY

The influence of thyrotropic hormone (TH) - Sigma (1 ME/kg b.m.) and t hyrotropin-releasing hormone (TRH) - Sigma (0.2 mg/kg b.m.) applied su bcutaneously once daily far three consecutive days on thrombocytopoies is and plasma thrombopoietin activity in male rats under physiological conditions is investigated. Ii is established that all parameters of thrombocytopoiesis are significantly increased as TH enhances platelet count by 75,74% (p<0.001) but TRH by 67.81% (p<0.002). Both hormones induce a statistically significant increase not only of the percentage of (75)Selenomethionine incorporated ino newly formed platelets (p<0. 001) but also of the number of cells from the megakaryocyte line (p<0. 001) which gives a proof of their positive influence upon this process . The parameters characterizing plasma thrombopoietin activity are sig nificantly elevated too (p<0.001). In conclusion, these data demonstra te that the doses of TH and TRH used stimulate considerably the thromb ocytopoiesis in rats. The increased plasma thrombopoietin activity res ults, most probably, from the activated biosynthesis of thrombopoietin as a basic humoral regulator of thrombocytopoiesis.