Abstract
A TRH test was performed in patients with Cushing's syndrome and isolated ACTH deficiency, and serum TSH was measured. A TRH-induced TSH showed low response in patients with Cushing's syndrome but showed excessive response in patients with isolated ACTH deficiency. However, in both diseases TRH-induced TSH response showed a tendency to normalize after the treatment.
Urinary 17-OHCS excretion was measured in patients with Cushing's syndrome and isolated ACTH deficiency before and after the treatment. There was a definite inverse correlation between the logarithm for urinary 17-OHCS excretion and the peak TSH response to TRH. These results suggested that glucocorticoids regulate not only ACTH but also TSH secretion.
