ELEVATED PLASMA-LEVELS OF VWFAG IN HYPERTHYROIDISM ARE MEDIATED THROUGH BETA-ADRENERGIC RECEPTORS

Thyroid dysfunction influences the levels of Von Willebrand actor (VWF :Ag). Plasma VWF:Ag levels in 35 hyperthyroid patients ere significant ly elevated, which had a positive correlation with both T3 (Triiodothy ronine) and T4 (Thyroxine) levels. A follow-up study of seven hyperthy roid patients undergoing anti-thyroid therapy showed that the elevated VWF:Ag levels returned to normal range with the normalization of thyr oid function. On the other and, after administration of 160 mg/day of propranolol, a specific locker of beta-adrenergic receptors, to five h yperthyroid patients or twenty-eight days, plasma VWF:Ag levels return ed to normal range, while T3, T4 levels remained high without signific ant alteration. These results demonstrated that the elevation of plasm a VWF:Ag by thyroid hormone is mediated through beta-adrenergic recept ors, which may be useful to further understand the physiological and p athological roles of thyroid hormone in the regulation of VWF:Ag level s.