The distribution kinetics of triiodothyronine: studies of euthyroid subjects with decreased plasma thyroxine-binding globulin and patients with Graves' disease

摘要: The kinetics of distribution 3,3',5-triiodo-L-thyronine (T(3)) have been studied employing both a single-injection and continuous infusion T(3-) (131)I. External monitoring radioactivity in the liver during permitted estimation hepatic volume (V(H)) one-way clearance (C(H)) hormone. Among 10 euthyroid control subjects, V(H) averaged 2.07 liters +/-0.50 (SD), mean value for C(H), 231 ml plasma per min (+/-64). In three men whose showed decreased binding capacity by thyroxine-binding globulin (TBG) abnormally high C(H) values were found, increase being proportional to decrease activity proteins. all 13 there was correlation (+ 0.86) between proportion free hormone plasma, measured vitro. four patients with hyperthyroid Graves' disease ranged from 3.2 4.2 elevated every case, averaging 989 ml/min. this group out elevation fraction plasma. Seven who either or hypothyroid after treatment slight but significant compared controls without disease. percentage treated normal low therefore could not explain persistent unidirectional observed. rate accumulation labeled T(3) tissues thigh interval 60 sustaining tracer slow equilibration did differ significantly among various groups studied. These latter findings suggest that slowly equilibrating such as are relatively insensitive alterations hormone-binding