The Role of the Thyroxine Loading Test in Diagnosing Defects of Thyroid Hormonobiogenesis

Year 1981, Volume: 34 Issue: 4, 621 - 638, 31.12.1981

Selahaddin Koloğlu

Abstract

Tiroid hormonlarının sentez, dönüşüm ve etkisindeki defektler, son yıllarda önem kazanmıştır. Bu defektler, tiroid patolojisinin genelinde nadir görülse de tiroidolojide büyük önem taşır. Mevcut tanı testlerinin sınırlılıkları, tiroid hormonbiyojenezine dair bozuklukların saptanmasında güçlük yaratmaktadır. Bu çalışmada, radyoaktif işaretli hormonların yerine, ağız yoluyla verilen işaretsiz tiroksin ile yapılan yükleme testi değerlendirilmiştir. A.Ü. Tıp Fakültesi Endokrinoloji Kürsüsünde sekiz dishormonojenez vakasında uygulanan test, T4'ün T3'e periferik dönüşüm defektlerini saptamada faydalı sonuçlar sağlamıştır. Bulgular, T4-toksikoz olgularında bu defektlerin olası rolüne işaret etmektedir faydalı sonuçlar sağlamıştır. Bulgular, T4-toksikoz olgularında bu defektlerin olası rolüne işaret etmektedir.

Tiroid Hormonobiyojenez Defektlerinin Tanısında Tiroksin Yükleme Testinin Yeri

Abstract

Defects in thyroid hormone synthesis, conversion, and action have gained increasing attention in recent years. Although rare in general thyroid pathology, they provide critical insight into thyroid physiology. Diagnostic challenges arise due to limitations in available tests. To address this, a non-radioactive thyroxine loading test was developed and assessed in eight cases of dishormonogenesis. Following oral administration of 3 mg thyroxine, serial hormone measurements were taken. The study demonstrated that this simple method could help identify peripheral conversion defects of T4 to T3. Observations also support a role for these defects in T4-toxicosis cases.

Keywords

thyroid hormonogenesis , thyroxine loading test , T4 to T3 conversion defect , dishormonogenesis , organification defect , Pendred syndrome , T4-toxicosis

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