[Serum level of thyroxin-binding globulin under oral contraception (author's transl)].

The use of oral contraceptives results in an increase in thyroid-binding-capacity in conformity with a change of results by T3/T4-tests. Using Laurell-electrophoresis and an anti-serum produced by Behringwerke the determination of the thyroid-binding-globulin (TBG) in serum is easy to handle. TBG was determined in serum from 137 women using oral contraceptives for more than 3 months. The apllication of oral contraceptives is followed by a statistically significant increase in the TBG level in serum. Thereby oral contraceptives change the TBG-level in a different degree. Preparations with a marked estrogen potency on the average effect a higher TBG-concentration than those with progesterone activity derived by menses-delay test. The difference of TBG-level is statistically significant. According by the increase of TBG-concentration in serum is caused by estrogen, the extent of the increase is modified by the progesterone component.