The conversion of thyroxine to 3,5,3'-triiodothyronine (T3) is the first step in thyroid hormone action, and the Type I iodothyronine deiodinase supplies most of this extrathyroidal T3 in the rat. We found that the cDNA coding for this enzyme contains an in-frame UGA encoding the rare amino acid selenocysteine. Using site-directed mutagenesis, we have converted selenocysteine to cysteine and ex...

Type III iodothyronine deiodinase (D3) catalyzes the inner ring deiodination (IRD) of T4 and T3 to the inactive metabolites rT3 and 3,3'-diiodothyronine (3,3'-T2), respectively. Here we describe the cloning and characterization of complementary DNA (cDNA) coding for D3 in fish (Oreochromis niloticus, tilapia). This cDNA contains 1478 nucleotides and codes for a protein of 267 amino acids, inclu...

As a tool with which to detect iodinated compounds in human thyroid specimens, we have reevaluated a nonincineration technique which has so far been employed in the determination of thyroxine-iodine in peripheral blood. The catalytic action of iodoamino acids in the Ce-As reaction was enhanced by a small amount of Cl2. On the contrary, a large amount of Cl2 inhibited the reaction unexpectedly. ...

Objective: To establish the reference intervals of thyroid stimulating hormone and free Tetraiodothyronine in healthy pregnant women Quetta, Baluchistan.
 Study Design: Cross-sectional study.
 Setting Duration: Combined Military Hospital, Quetta Pakistan, at Jun 2018 to 2019.Methodology: Consecutive blood samples (in all three trimesters) were taken analyse Tetra-iodothyronine by elec...

We investigated transport systems for tri-iodothyronine (T(3)) and thyroxine (T(4)) in the human choriocarcinoma cell line, JAR, using a range of structurally similar compounds to determine whether these thyroid hormones are transported by common or different mechanisms. Saturable T(3) but not saturable T(4) uptake was inhibited by a wide range of aromatic compounds (nitrendipine, nifedipine, v...

Chromium in hexavalent form is highly toxic and a known carcinogen, although its effects on thyroid structure and function are relatively unexplored. Workers in an industrial environment can be, at times, exposed to this form of chromium. The present study was, therefore, designed using laboratory rats as a model system to investigate the effect on thyroid structure and function following two a...