CIRCADIAN-RHYTHM OF TSH SECRETION IN PATIENTS WITH ADDISONS-DISEASE BEFORE AND AFTER GLUCOCORTICOID REPLACEMENT THERAPY

We investigated the circadian rhythm of TSH secretion in patients with primary adrenal insufficiency, Addison's disease, before and after gl ucocorticoid replacement therapy. The findings observed in our patient s showed elevated TSH levels, no circadian variation of TSH secretion both before and after glucocorticoid replacement therapy, normal triio dothyronine and thyroxine levels, normal TSH following TRH stimulation , a significant decrease of TSH levels following corticoid administrat ion. These results confirm previous data showing that glucocorticoids play an inhibitory role in the regulation of TSH secretion and indicat e a failure of the circadian TSH rhythm, in Addison's disease.