Thyrotropin, total thyroxine, thyroxine binding capacity and free thyroxine index in patients with gonadal dysgenesis (karyotype 45/XO).

In 9 patients with gonadal dysgenesis (karyotype 45/XO), the responsiveness of thyreotropic cells of the pituitary was investigated by stimulation with thyreotropin-releasing hormone (TRH). Both after hormone substitution in the form of sequential therapy (mestranol/mestranol-chlormadinone acetate) and after the end of therapy the investigations were repeated. TSH was determined by RIA, total thyroxine and binding capacity of thyroxine binding globuline (TBC-index) by protein binding assay. The free thyroxine index (FT4-index) was calculated. The results show that the hypothalamic-pituitary unit in patients with gonadal dysgenesis reacts in a similar manner as in normal female subjects.