Elevated plasma levels of VWF:Ag in hyperthyroidism are mediated through beta-adrenergic receptors

Thyroid dysfunction influences the levels of Von Willebrand factor (VWF:Ag). Plasma VWF:Ag levels in 35 hyperthyroid patients were significantly elevated, which had a positive correlation with both T3 (Triiodothyronine) and T4 (Thyroxine) levels. A follow-up study of seven hyperthyroid patients undergoing anti-thyroid therapy showed that the elevated VWF:Ag levels returned to normal range with the normalization of thyroid function. On the other hand, after administration of 160 mg/day of propranolol, a specific blocker of beta-adrenergic receptors, to five hyperthyroid patients for twenty-eight days, plasma VWF:Ag levels returned to normal range, while T3, T4 levels remained high without significant alteration. These results demonstrated that the elevation of plasma VWF:Ag by thyroid hormone is mediated through beta-adrenergic receptors, which may be useful to further understand the physiological and pathological roles of thyroid hormone in the regulation of VWF:Ag levels.