THYROID-FUNCTION IN NONGROWTH HORMONE-DEFICIENT SHORT CHILDREN DURING A PLACEBO-CONTROLLED DOUBLE-BLIND TRIAL OF RECOMBINANT GROWTH-HORMONE THERAPY

GH treatment in GH-deficient children has been reported to cause decreases in serum T-4 and TSH and an increase in serum T-3. We sought to determine whether GH treatment alters thyroid function in non-GH-deficient short children. Twenty children (18 boys) mere followed for 12 months while receiving either GH (Humatrope, Eli Lilly; 0.074 mg/kg, sc, 3 times/week; n = 9) or placebo (n = 11). Total T-4, free T-4, T-3, and TSH were measured every 6 months and in 12 children also at 1, 2, 3, and 9 months. A TRH test and measurement of nocturnal TSH surge were performed at baseline and after 6 months of treatment in 19 subjects. There were no significant differences at baseline in the clinical features between the placebo and GH groups. Total T-4, free T-4, T-3, and TSH levels did not significantly differ between the placebo and GH groups at baseline and at 1, 2, 3, 6, 9, and 12 months. There were no significant differences between the two groups in TSH response to TRH or nocturnal TSH surge. Although an early transient effect of GH treatment could not be excluded, we conclude that GH treatment for 12 months does not produce sustained alterations in thyroid function in non-GH-deficient children.