Bermudez F, Surks M I, Oppenheimer J H
J Clin Endocrinol Metab. 1975 Jul;41(1):27-40. doi: 10.1210/jcem-41-1-27.
Serum thyroxine (T4) and triiodothyronine (T3) concentration and binding were measured in 34 clinically euthyroid patients hospitalized for a wide variety of nonthyroidal diseases. Despite clinical euthyroidism, serum T3 was in the hypothyroid range (less than 90 ng/100 ml) in 24 of the 34 patients, and the mean serum T3 of this group, 78.4 +/- 38.3 (SD), was significantly decreased from that of control, 134.0 +/- 29.3 ng/200 ml. Mean serum T4 levels were essentially the same in both groups, 7.3 +/- 2.0 for sick patients and 7.2 +/- 1.0 mug/100 ml for the controls. Plasma binding of both T4 and T3 was decreased in the patient group to 69.9 and 78% of control values, respectively. In accord with previous studies, the mean free T4 index, proportional to free T4 concentration, was significantly increased to 10.0 +/- 4.1 in the patient group (control, 7.6 +/- 1.3). However, the mean free T3 index of the patient group, 92.9 +/- 38.4 remained decreased from that of control, 138.9 +/- 34.4. Of the 24 patients with decreased serum T3 (less than 90 ng/100 ml), low T3 levels could be attributed to decreased plasma binding in 8; in 5, serum T3 was within the normal range for their advanced age. Mean TSH was greater in the patient group 2.6 +/- 1.9, than in the controls, 1.9 +/- 1.1 muU/ml. Moreover, the TSH response to administered TRH was moderately exaggerated in 7 patients with low free T3 index compared to 7 patients with normal free T3 index. Although significant statistically, neither the basal nor TRH induced TSH levels were in the range generally found in primary hypothyroidism. The data suggest that the high incidence of low serum T3 (70%) and free T3 index (32%) in nonthyroidal disease may be related to the catabolic state that accompanies illness rather than to specific disease entities. At the present time, the use of serum T3 or free T3 measurements for the diagnosis of hypothyroidism does not appear justified in patients with nonthyroidal disease.
对34名因各种非甲状腺疾病住院的临床甲状腺功能正常的患者，测定了血清甲状腺素（T4）、三碘甲状腺原氨酸（T3）的浓度及结合情况。尽管临床甲状腺功能正常，但34名患者中有24名患者的血清T3处于甲状腺功能减退范围（低于90 ng/100 ml），该组患者的血清T3均值为78.4±38.3（标准差），显著低于对照组的134.0±29.3 ng/200 ml。两组患者的血清T4均值基本相同，患病患者为7.3±2.0，对照组为7.2±1.0 μg/100 ml。患者组中T4和T3的血浆结合率分别降至对照组值的69.9%和78%。与先前的研究一致，与游离T4浓度成正比的平均游离T4指数在患者组中显著升高至10.0±4.1（对照组为7.6±1.3）。然而，患者组的平均游离T3指数92.9±38.4仍低于对照组的138.9±34.4。在血清T3降低（低于90 ng/100 ml）的24名患者中，8名患者T3水平降低可归因于血浆结合率降低；5名患者的血清T3处于与其高龄相符的正常范围内。患者组的平均促甲状腺激素（TSH）水平高于对照组，分别为2.
