Endocrine Abstracts

Acetylation of DNA can result in gene silencing. In the thyroid such phenomena can lead to the loss of ability to accumulate radioiodide. The aim of this study was to examine the effects on the rat thyroid cell line FRTL-5 and human thyroid follicular cancer cell line FTC-133 of Trichostatin A (TSA), a histone deactylase inhibitor. A concentration of TSA was selected using MTT cell viability assays for use in uptake, efflux and expression studies. Cells were incubated with TSA...

Epigenetic phenomena such as methylation or acetylation of DNA can result in transcriptional inactivation and gene silencing. In the thyroid such phenomena can bring about the loss of ability to accumulate iodide as a result of methylation of CpG islands in human sodium iodide symporter (NIS) and Pendrin (PDS) DNA, limiting the ability to utilise radioiodide therapy. This study examines the effects of Trichostatin A (TSA) a histone deacetylase (HDAC) inhibitor on a rat thyroid...

Uptake of ingested iodide (I-) in the thyroid is achieved through an active transport system, the sodium iodide symporter (NIS). The gland has the ability to accumulate I- from the bloodstream by a factor of 20-40. Seaweeds, which in vivo bear the same relationship to seawater, as does the thyroid to the bloodstream, have a dramatically more efficient I- uptake system, accumulating I- from seawater by a factor of anything up to 1 mil...

Seaweed consumption results in high levels of iodine intake in Asian populations and influences the presentation of thyroid and perhaps extrathyroidal disorders. The relationship of seawater to seaweed is analogous to that between the bloodstream and the thyroid. However, seaweed has a dramatically more efficient uptake system than the thyroid, concentrating iodide from seawater by a factor of up to 106 compared to 40-50 for the thyroid. The ability of seaweeds to b...

The demonstration in extrathyroidal tissues of the sodium iodide symporter (NIS) has raised the possibility that 131I, commonly used as a therapeutic ablative agent in hyperthyroidism and thyroid cancer, might be applied in the treatment of tumours in other NIS expressing tissues such as human breast cancer. As thyroidal uptake of 131I is known to be inversely proportional to circulating stable I- concentration, the aim of this study was to determine how I- would effect such u...

Expression of the Sodium Iodide symporter (NIS) in the breast was thought to be restricted to lactation but recently have been shown in breast cancer and benign breast disease. CpG island methylation of the promoter region of NIS is known to decrease iodide uptake in the thyroid. No such information has been documented in the breast. The aim of this study was to investigate the effect of demethylating agents on iodide uptake in breast cancer cell lines MCF-7 (oestrogen (E) and...

Synthesis of thyroid hormones by the fetal thyroid requires the passage of iodide through the placenta. In the thyroid active iodide transport is facilitated by three transporters, the sodium iodide symporter (NIS), Pendrin (PDS) and the recently described the human apical iodide transporter (hAIT). Simultaneous expression of all three transporters appears to be thyroid restricted and although extrathyroidal expression of individual transporters has been reported, relatively l...

This study aims to recruit 22,000 women in early gestation to screen for thyroid failure. The trial is randomised such that half the women are being tested in early gestation (group1) while the remainder (group 2) are tested after delivery. As T4 is important for the developing foetal brain, the IQ of the children from group 1, whose mothers will have been treated with T4, is expected to be higher than that from group 2.Women are entered on the basis of ...

The relationship between serum TSH and thyroid autoantibodies is frequently used to classify thyroid disease both overt and subclinical. Further debate has centred on the validity of the cutoff point for serum TSH elevation (generally between 4-5 mU/l) which it has been suggested is inappropriately high. The significance of the presence of thyroid autoantibodies (hereafter termed antibody positivity) in extrathyroidal disease is unclear but an increased prevalence has been rep...