Abstract
Coagulation and fibrinolysis after hypophysectomy were studied in Wistar rats. Hypophysectomy by aspiration or sham-operation by the same procedure without touching the pituitary gland was performed on day 0. Various parameters of coagulation and fibrinolysis were examined on days 21 and 35. In rats that had undergone hypophysectomy, significant decreases in erythrocyte count, hematocrit, and hemoglobin concentration were observed on day 35 compared with those in sham-operated and control groups. The prolongation of r and k values and a decrease in ma value on thromboelastogram were observed on day 21, and r value was also prolonged on day 35. A significant decrease in fibrinogen level was observed on day 35 and an increase in the activity of factor XIII was found on days 21 and 35. Results of hepaplastin tests were lower on days 21 and 35. Antithrombin III activity and plasminogen level were higher on day 35. These results suggest that hypophysectomy suppresses coagulation and enhances fibrinolysis. These results also support the hypothesis that the pituitary gland influences the balance between blood coagulation and fibrinolysis.
