Chopra I J, Chopra U, Smith S R, Reza M, Solomon D H
J Clin Endocrinol Metab. 1975 Dec;41(06):1043-9. doi: 10.1210/jcem-41-6-1043.
Serum concentrations of 3,3',5'-triiodothyronine (reverse T3, rT3) were measured in adult patients with several systemic illnesses whose serum total and/or free T3 were low, serum total T4 was low or normal, and free T4 was either normal or elevated. The mean serum rT3 was 76, 46, and 77 ng per 100 ml in patients with hepatic cirrhosis, chronic renal failure, and acute febrile illnesses, respectively; the values in patients with hepatic cirrhosis and acute febrile illness were significantly higher than, and values in patients with renal failure did not differ significantly from, the mean serum rT3 (41 ng per 100 ml) in normal subjects. The mean serum rT3 in another group of patients from Calcutta, India, who had severe protein calorie malnutrition (PCM), was 53 ng per 100 ml; it was significantly higher than the corresponding value, 22 ng per 100 ml, in the same patients after feeding treatment. Mean serum rT3 in patients with systemic illnesses was not so high as that (151 ng per 100 ml) in the normal newborn, who also has low serum T3 and normal or high T4. High serum rT3 in patients with systemic illness could not be attributed to increased serum protein binding of rT3; whenever studied, the dialyzable fraction of rT3 was not decreased but actually increased. The mean serum-free rT3 was 450,207, and 366 pg per 100 per 100 ml in patients with hepatic cirrhosis, chronic renal failure, and acute febrile illnesses, respectively; each of these values was significantly higher than the corresponding value, 98 pg per 100 ml, in normal subjects. The mean serum free rT3, 516 pg per 100 ml, in newborn cord sera was similar to that in patients with hepatic cirrhosis but was higher than that observed in patients with chronic renal failure and acute febrile illnesses. High serum rT3 and low serum T3 in patients with PCM improved to normal or towards normal after feeding treatment. Since the peripheral metabolism of T4 is normally the predominant source of T3 as well as rT3 in man, our data, demonstrating reciprocal changes in serum rT3 and T3 and no consistent change in serum T4, suggest that body metabolism of T4 may be so altered in systemic illness that the conversion of T4 to rT3 may be increased while that to T3 is decreased. The mechanism or the biological significance of such a diversion of T4, from the normally occurring conversion to highly potent T3, to the generation of poorly calorigenic rT3 in systemic illness, is not clear at this time. The data in patients with PCM demonstrate, however, that such a change in the metabolism of T4 can be reversible.
在患有多种全身性疾病的成年患者中，检测了血清3,3',5'-三碘甲状腺原氨酸（反三碘甲状腺原氨酸，rT3）的浓度。这些患者的血清总T3和/或游离T3较低，血清总T4较低或正常，游离T4正常或升高。肝硬化、慢性肾衰竭和急性发热性疾病患者的血清rT3平均浓度分别为每100 ml 76、46和77 ng；肝硬化和急性发热性疾病患者的值显著高于正常受试者的血清rT3平均浓度（每100 ml 41 ng），而肾衰竭患者的值与正常受试者的值无显著差异。另一组来自印度加尔各答、患有严重蛋白质热量营养不良（PCM）的患者，其血清rT3平均浓度为每100 ml 53 ng；在喂养治疗后，同一组患者的相应值为每100 ml 22 ng，显著低于治疗前。患有全身性疾病的患者血清rT3平均浓度不如正常新生儿（血清T3低，T4正常或高）的高（每100 ml 151 ng）。全身性疾病患者血清rT3升高不能归因于rT3的血清蛋白结合增加；无论何时进行研究，rT3的可透析部分并未降低，实际上反而增加。肝硬化、慢性肾衰竭和急性发热性疾病患者的血清游离rT3平均浓度分别为每100 ml 450、207和366 pg；这些值均显著高于正常受试者的相应值（每100 ml 98 pg）。新生儿脐血血清中的血清游离rT3平均浓度为每100 ml 516 pg，与肝硬化患者的相似，但高于慢性肾衰竭和急性发热性疾病患者的值。PCM患者血清rT3升高和血清T3降低在喂养治疗后改善至正常或接近正常。由于在人类中，T4的外周代谢通常是T3以及rT3的主要来源，我们的数据表明血清rT3和T3呈反向变化，血清T4无一致变化，这表明在全身性疾病中，T4的体内代谢可能发生改变，以至于T4向rT3的转化可能增加，而向T3的转化可能减少。在全身性疾病中，T4从正常转化为高效能的T3转而生成产热能力差的rT3，这种转变的机制或生物学意义目前尚不清楚。然而，PCM患者的数据表明，T4代谢的这种变化是可逆的。
