[Changes of thyroid hormone levels during ACTH therapy in epileptic children]

To investigate the effect of ACTH on thyroid function, thyroid hormone levels were measured in twelve patients with epileptic children who were treated with ACTH. One week after daily administration of ACTH, serum T3, T4, TSH, thyroglobulin and T3/T4 ratio showed significantly lower values compared with those of pretreatment values (p < 0.001-p < 0.05). Thyroid hormone levels respectively showed negative correlation with cortisol levels before and one week after ACTH treatment respectively. Tapering of ACTH brought a rapid recovery of T3, T4, TSH and thyroglobulin levels with concomitant return of plasma cortisol levels to the normal range. These results suggested that excess ACTH suppressed thyroid hormone secretion mainly through a decreased TSH secretion and a peripheral conversion of T4 to T3 by increased cortisol levels.