[TBG isoforms in the course of hyperthyroidism].

In 7 hyperthyroid patients on the one hand thyroxine-binding globulin (TBG) was determined by commercially available radioimmunoassay and on the other hand TBG-isovariants were established by means of isoelectric focusing. For assessment blood samples were taken upon admittance to our hospital and 2 and 4 weeks thereafter, respectively, during antithyroid drug treatment. A comparative series of 10 euthyroid subjects were equally evaluated. Both groups showed no significant differences of TBG values at onset and in the course of antithyroid treatment. However, TBG isovariants showed significant decreases in anionic bands (pH 4.25 to 4.45) whereas a significant increase in cathodic bands (pH 4.55 to 4.65) at onset of treatment compared to the euthyroid control group could be observed. During the course of antithyroid treatment the values of TBG-isobands reversed reaching the pattern of normal group. In contrast to the recent research by Hashizume et al. we observed no reduction in TBG level in hyperthyroid patients although a significant shift in the TBG isovariants could be established. Due to the antithyroid treatment prescribed, the TBG isovariants finally reached the normal pattern of euthyroid controls.