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Biomedical Research,. 1991. Plasma Selenium Concentrations in Patients with Euthyroid Sick Syndrome ... bition of conversion, including abnormal protein bind- ing(6). ..... Plasma sele- nium concentrations have been shown to be responsive.
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CLIN.CHEM.38/9, 1885-1888 (1992)

Plasma Selenium Concentrations in Patients with Euthyroid Sick Syndrome Frederick

Van Lente’ and Rose Daher”2

We evaluated plasma selenium concentrations in patients with euthyroid sick syndrome express by low serum triiodothyronine (T3) concentrations. Selenium status in these patients was compared with that found in patients with both untreated and treated hypothyroidism.Selenium concentrations in plasma were significantly lower in hospitalized patients with either euthyroid sick syndrome (0.99 ± 0.37 unol/L) or treated hypothyroidism (1.09 ± 0.25 1zniol/L) than in patients with untreated hypothyroidism (1.39 ± 0.28 moVL). However, there was no significant, independent relationship between selenium and the thyroid function indices determined in this study. The strongest association was between serum albumin concentration and either selenium (r = 0.65), T3 (r = 0.58), or the molar ratio of T3 to thyroxine (r = 0.64). The decreased average selenium concentration appears to be associated with the hypercatabolic state of severely ill patients, as indicated by the serum albumin concentration; these patients should be considered for selenium supplementation and their selenium status should be monitored. Addftlonal Keyphras.s:

thyroid function

nutrition

is an essential trace metal for human meand is required for the expression of glutathione peroxidase (GPX; EC 1.11.1.9) activity.3 It was shown recently that selenium is also present in Type I iodothyronine 5’-deiodinase found in mammalian tissue (1). This finding has rekindled interest in the role of selenium status in thyroid disease (2-4). Many patients with the so-called euthyroid sick syndrome demonstrate decreased triiodothyronine (T3) concentrations in serum. Decreased peripheral conversion Selenium

tabolism

‘Department of Biochemistry, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH 44195. 2Department of Chemistry, Cleveland State University, Euclid Ave. at East 24th St., Cleveland, OH 44115. 3Nonstandard abbreviations: GPX, glutathione peroxidase; T3, triiodothyronune; T4, thyroxine; TSH, thyrotropin; T4U, thyroxine uptake; and Y1’4h,free thyroxine index. Received January 9, 1992; accepted April 24, 1992.

of thyroxine (‘F4)to T3 in the absence of thyroid dysfunction, indicated by a normal thyrotropin (‘NH) concentration, is thought to be responsible for this effect (5,6). Many factorS have been postulated to explain this inhibition of conversion, including abnormal protein binding(6). We choseto study plasma selenium concentrations in patients with nonthyroid illness and both treated and untreated hypothyroidism who had decreased T3 concentrations in serum. We evaluated the relationship of selenium concentrations to the degree of thyroxine conversion as reflected in the T3fF4 ratio, in relation to other laboratory indices. Materials and Methods Sixty-seven patients having T3 concentrations