The influence of growth hormone monotherapy and growth hormone in combination with oxandrolone or testosterone on thyroxid hormone parameters and thyroxin binding globulin in patients with Ullrich-Turner syndrome

Administration of human growth hormone (GH) has yielded conflicting results concerning its role on thyroid function in patients with Ullrich-Turner syndrome. Therefore, we investigated the course of thyroid hormone parameters and thyroxin binding globulin in relation to GH therapy, IGF-I and additional oxandrolone-(Ox) or testosterone (T) treatment in 20 patients with Ullrich-Turner syndrome. During the Ist year the patients received only GH. There was no change in T4, fT4, and TSH levels, T3 increased significantly (P < 0.01) after 6 and 12 months, resulting in a higher T3/T4 ratio. TBG (P < 0.05) and IGF-I (P < 0.01) increased after 6 months and remained elevated at 12 months. A significant positive correlation was found between the change of T4 and TBG after 6 months (r = 0.47, P < 0.05) and after 12 months (r = 0.69, P < 0.005). Thirteen patients were further investigated after addition of an anabolic compound; 7 received Ox (0.0625 mg/kg/day po) and 6 low dose T (5 mg i.m. every 14 days). Chronological age was comparable in these groups (10.7 +/- 2.7 vs 10.7 +/- 3.6 years). After 6 months of combination therapy with Ox, T4, T3 and TSH decreased. As T4 and T3 showed a parallel decrease the T3/T4 ratio remained elevated. TBG declined after 6 and 12 months (P < 0.05), while IGF-I showed a further increment (P < 0.05). There was no correlation between the changes in T4 and IGF-I, TSH and TBG, respectively. In the T-treated group only IGF-I increased (P < 0.05) to the same extent as in the Ox-treated patients, whereas the thyroid parameters did not change. Conclusion The observed changes in thyroid hormone and TBG levels in the Ox group were not mediated by GH or IGF-I. The Ox-induced TBG decrease might be linked to altered pancreatic functions regulating carbohydrate metabolism.