Földes J, Tarján G, Bános C, Németh J, Varga F, Büki B
First Department of Medicine, Semmelweis University Medical School, Budapest, Hungary.
Acta Med Hung. 1991;48(1-2):33-43.
Plasma fibronectin, serum procollagen-III-peptide and sex-hormone-binding globulin as non-specific markers of thyroid hormone effect at peripheral tissue level were determined and their values were related with serum levels of TSH, free-thyroxine and triiodothyronine during levothyroxine sodium replacement therapy for hypothyroidism. Low levels of biologic markers characteristic of hypothyroidism were normalized in consequence of hormone replacement and a negative correlation between their serum levels, and TSH concentration was demonstrated in most subjects. However, in some patients a discrepancy in the response to levothyroxine between the pituitary and other target organs was revealed. Additional evidence was disclosed that the pituitary thyrotroph sensitizes a minor decrease in serum thyroxine level, which would not be recognized by other target organs. Furthermore, it was revealed that during L-T4 replacement therapy in a large fraction of patients with subnormal serum TSH concentration blood levels of the measured markers often exceeded the upper limit of the normal range indicating a possibility of "tissue" thyrotoxicosis, besides the pituitary, in other target organs, too. According to the present study, which takes into consideration markers reflecting end-organ responsiveness to thyroid hormones, it is recommended to adjust the dose of levothyroxine to maintain serum TSH in the normal range. For patients with subnormal TSH concentration a close follow-up is obligatory and in case of concomitantly raised free-thyroxine level the reduction of the levothyroxine dosage is proposed.
测定了血浆纤连蛋白、血清Ⅲ型前胶原肽和性激素结合球蛋白，作为甲状腺激素在外周组织水平作用的非特异性标志物，并将其值与甲状腺功能减退患者左甲状腺素钠替代治疗期间的血清促甲状腺激素（TSH）、游离甲状腺素和三碘甲状腺原氨酸水平相关联。甲状腺功能减退的特征性低水平生物标志物因激素替代而恢复正常，且在大多数受试者中显示出它们的血清水平与TSH浓度之间呈负相关。然而，在一些患者中，垂体和其他靶器官对左甲状腺素的反应存在差异。有更多证据表明，垂体促甲状腺细胞对血清甲状腺素水平的轻微下降敏感，而其他靶器官则无法识别这种下降。此外，研究发现，在大部分血清TSH浓度低于正常水平的患者进行左甲状腺素（L-T4）替代治疗期间，所测标志物的血水平常常超过正常范围上限，这表明除垂体外，其他靶器官也可能发生“组织”甲状腺毒症。根据本研究，考虑到反映终末器官对甲状腺激素反应性的标志物，建议调整左甲状腺素剂量以维持血清TSH在正常范围内。对于TSH浓度低于正常水平的患者，必须密切随访，若同时游离甲状腺素水平升高，则建议减少左甲状腺素剂量。
