The Radiothyroxine Turnover Study in the Diagnosis of Thyroid Disease

Publisher Website
Google Scholar
Abstract
Radiothyroxine turnover studies were performed in a group of 34 patients with a variety of thyroid disorders in an effort to resolve problems of clinical and theoretical interest. The results obtained indicate that determination of radiothyroxine turnover may be of considerable diagnostic value in circumstances where routine laboratory thyroid function studies are either contradictory or inconclusive. The characterization of thyroid function by study of radiothyroxine turnover was found to be of major importance in the clinical evaluation of the treated hyperthyroid patient; it was also of significant diagnostic import in the assessment of clinically borderline hyperthyroidism as well as in patients on exogenous estrogen therapy. The limitations of routine thyroid function studies in these various circumstances are noted, although the primacy of these routine procedures in the initial laboratory evaluation of suspect thyroid dysfunction is stressed. Results obtained in hyperthyroid patients treated with guanethidine, with resulting depletion of body catecholamines, indicate that although biologic activity of circulating thyroid hormone is modified in these circumstances, no alteration of thyroid hormone economy occurs. The data obtained with this drug is an athyreotic cretin on thyroid hormone replacement therapy suggest that normal body catecholamine stores are not a requisite for biologic activity of exogenous thyroid hormone nor is peripheral metabolism of administered thyroxine altered in these circumstances. It is concluded that the rate of removal of an intravenously administe-red dose of radiothyroxine is a valid and meaningful parameter of thyroid function.

This publication has 17 references indexed in Scilit: