Journal of Clinical Endocrinology & Metabolism, Vol 58, 1184-1187, Copyright © 1984 by Endocrine Society

ARTICLES

Reverse triiodothyronine does not alter pituitary-thyroid function in normal subjects

BL Shulkin and RD Utiger

Serum rT3 concentrations are often increased in patients with nonthyroid illness. Such elevations could be responsible for some of the alterations in pituitary-thyroid function that occur in such patients, particularly since rT3 is a potent inhibitor of extrathyroidal T3 production in vitro. To evaluate the role of serum rT3 elevations in the regulation of the hypothalamic-pituitary-thyroid axis, 10 normal subjects were given 3 mg rT3, orally, in divided doses for 4 days. Serum rT3 concentrations were elevated at least 10-fold by the end of the first day of treatment. Mean serum T4 and T3 concentrations did not change, nor was there any change in basal or TRH- stimulated serum TSH concentrations. There was, likewise, no change in serum binding of T3 or T4. These results show that rT3, given orally, has no detectable activity in normal subjects, and hence, elevations in serum rT3 concentrations per se do not contribute to other abnormalities in thyroid function found in patients with nonthyroid illness.

This article has been cited by other articles:

				P Cettour-Rose, T J Visser, A G Burger, and F Rohner-Jeanrenaud Inhibition of pituitary type 2 deiodinase by reverse triiodothyronine does not alter thyroxine-induced inhibition of thyrotropin secretion in hypothyroid rats Eur. J. Endocrinol., September 1, 2005; 153(3): 429 - 434. [Abstract] [Full Text] [PDF]

				J. Lei, S. Nowbar, C. N. Mariash, and D. H. Ingbar Thyroid hormone stimulates Na-K-ATPase activity and its plasma membrane insertion in rat alveolar epithelial cells Am J Physiol Lung Cell Mol Physiol, September 1, 2003; 285(3): L762 - L772. [Abstract] [Full Text] [PDF]