the concentration of serum thyroxine ( t4 ) -binding globulin ( tbg ) not binding t4 ( unsaturated tbg , u-tbg ) was determined in hyper- and hypothyroidism . u-tbg was expressed as the product of tbg concentration and the ratio of free tbg capacity to maximal tbg capacity as determined by reverse-flow electrophoresis . u-tbg concentration in normal sera ( n = 40 ) was 15.5 +/- 2.3 mg/l ( mean +/- sd ) , or 257 +/- 38 nmol/l for a molecular weight of tbg of 60 000 daltons . u-tbg levels were significantly lower in hyperthyroidism ( 7.1 +/- 2.3 mg/l , n = 16 , p less than 0.001 ) and higher in hypothyroidism ( 21.7 +/- 5.0 mg/l , n = 22 , p less than 0.001 ) .
C0040165
thyroxine
C0020676
hypothyroidism