Five families with inherited thyroxine-binding globulin (TBG) abnormalities were studied. On the basis of serum thyroxine (T(4))- binding capacity of TBG in affected males, three family types were identified: TBG deficiency, low TBG, and high TBG capacity. In all families evidence for X-linked inheritance was obtained and in one family all criteria establishing this mode of inheritance were met...

We describe a new double-antibody enzyme radioimmunoassay for thyroxin-binding globulin (TBG) in serum. A TBG-beta-D-galactosidase complex was prepared with m-maleimidobenzoyl N-hydroxysuccinimide ester. The mean analytical recovery of TBG added to serum was 99%, sample volume and TBG value were linearly related, and values for TBG determined by this method and those determined by radioimmunoas...

It has been previously suggested that inherited thyroxine-binding globulin (TBG) abnormalities in man may be due to mutations at a single X-chromosome-linked locus controlling TBG synthesis. However, abnormalities in TBG degradation have not been excluded. The availability of purified human TBG and its successful labeling with radioiodide allowed us to examine such possibility. Human TBG was pu...

The incidence of complete thyroxine-binding globulin (TBG) deficiency (TBG-CD) was determined for a Japanese population from a comprehensive health examination, in which a T3 resin uptake test of the upper 5% (78 subjects from among 1,589 men) was the screening line for TBG-CD. Further analysis of the known mutation in TBG-CD gene of the Japanese population (reported as TBG-CDJ with codon 352 d...

We studied the dependence of the free thyroxin (T4) index and the ratio of T4 to thyroxin-binding globulin (TBG) on TBG concentrations, using sera from cases of congenital TBG deficiency and congenital TBG excess. Two such sera with similar concentrations of albumin, transthyretin, and free T4 were mixed to provide test samples with TBG concentrations covering the range of clinical interest wit...

The concentration of thyroxine-binding globulin (TBG) in the serum can now be measured by direct assays that are simple and inexpensive. Comparison of a direct measurement of TBG concentration with a widely used indirect method (Thyopac-3) showed that the indirect method was inaccurate when TBG concentrations were high. This will result in an increase in the derived free thyroxine index (FTI), ...

Objective: It is generally thought that thyroxine-binding globulin (TBG)-deficient individuals are euthyroid and do not require treatment. However, there have been case reports of TBG deficiency combined with hypothyroidism. The purpose of this study was to investigate the relationship between TBG deficiency and thyroid function. Methods: We reviewed the medical records of 32 patients diagnosed...

A new method for the estimation of the maximal T4-binding capacity of TBG (max. TBG) in serum (dextran-coated charcoal-triosorb method) was devised. Thyroxine (T4) concentration in test sera were determined by the Tetrasorb method and then T3 resin sponge uptake (T3 RSU) was determined after extraction of 70% of the endogenous T4 with dextran-coated charcoal. The binding capacity of unsaturate...

Serum thyroxine-binding globulin (TBG) in 169 patients with various cancers was determined by radioimmunoassay (RIA). Eleven patients showed a high serum TBG level (greater than 35 micrograms/ml). Two of them had been treated with estrogen for prostate cancer. One patient had high serum TBG with serum hepatitis. Another 8 cases had normal liver function and also normal levels serum estrogen. Th...

A method is described for the determination of thyroxine binding globulin (TBG) in dried blood spotted on filter paper using reagents from a test kit for the measurement of TBG in plasma. By minor modifications of the recommended procedure it was possible to improve precision, sensitivity and tracer displacement. Appropriate TBG standard samples were prepared in 'artificial blood' consisting of...