Fibronectin during thyroid hormone replacement therapy.

Hemostasis may be affected by thyroid function in various ways. We studied plasma concentration of Fibronectin in 13 untreated patients after total thyroidectomy due to thyroid carcinoma. Fibronectin levels were significantly decreased compared to an equal numbered group of healthy volunteers (p 0.0005). The same patients were studied again after an oral thyroid replacement of 200 micrograms L-thyroxine/d over at least six weeks. Fibronectin had increased significantly, compared to untreated patients and controls resp. Furthermore, a significant positive correlation was found between plasma concentrations of Fibronectin and total T4 (r = 0.92; y = 6.617 + 0.52x). In contrast Factor V activity was low in untreated patients but normal during high dose replacement therapy. No correlation was found between Factor V and thyroid hormone concentrations. We discuss the relation between fibronectin plasma levels and thyroid hormones.