- The Aging-related Change of Responses to TSH in Thyroid Cells.
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Young Joo Park, Tae Yong Kim, Ji Eun Kim, Young Cheol Kim, In Kyeong Chung, Chan Soo Shin, Do Joon Park, Kyoung Soo Park, Seong Yeon Kim, Sang Chul Park, Hong Kyu Lee, Bo Youn Cho
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J Korean Endocr Soc. 2004;19(2):141-151. Published online April 1, 2004
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 Abstract
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- BACKGROUND
To understand the mechanism of aging-related changes of the thyroid, the differentiated functions and growth of thyroid cells in response to TSH were investigated using aged or young thyrocytes. METHODS: FRTL-5 cells, with less than 10 or more than 45 passages, were used. After treatment with 1 U/L TSH or 1-100 mM NaI, the cAMP generation, iodide uptake, cellular proliferation or the expression of NIS mRNA or protein were measured. Sprague-Dawley rats were sacrificed at 5 and 16 weeks and 23 months, and their thyroids used for Northern blot analysis or immunohistochemistry of NIS. RESULTS: There were no differences in cAMP generation, iodide uptake, the proportions of G1/M or S phase, or intracellular DNA contents between the young and aged cells at basel levels. After TSH stimulation, these were increased in dose-dependent manners, with larger increments in the young cells. The changes in the NIS mRNA expression were similar in both the young and aged cells, but to a greater extent in the young cells. A similar phenomenon was observed in rat. However, the amount or intracellular distribution of NIS protein was not different. There was also no difference in the function or expression of NIS after treatment with a high dose of iodide. CONCLUSION: The aging-related decrease in the generation of cAMP might be thought of as one of the mechanisms of the decrement of iodide uptake or cellular proliferation with aging. The decreased expression of NIS mRNA seems to be the most important mechanism for the decreased iodide uptake capacity
- The Changes of Expression of Thyroid Specific Antigens in Aging.
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Young Joo Park, Eun Shin Park, Tae Yong Kim, Sang Wan Kim, Hyeong Kyu Park, Do Joon Park, Won Bae Kim, Chan Soo Shin, Kyoung Soo Park, Seong Yeon Kim, Sang Chul Park, Hong Kyu Lee, Bo Youn Cho
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J Korean Endocr Soc. 2001;16(4-5):457-466. Published online October 1, 2001
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Abstract
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- BACKGROUND
With the prevalence of serum antithyroglobulin(anti-TG) and antithyroperoxidase(anti-TPO) autoantibodies increasing with age, it has been suggested that changes of thyroid autoimmunity with aging are associated with endemic iodine intake. To understand the mechanism of aging-related increases of thyroid autoimmune response, we investigated the expression of thyroid specific autoantigens of aged phenotype, and compared them with those of young phenotype both in vivo and in vitro. METHODS: Sprague-Dawley rats were sacrificed at 5, 10 and 16 weeks(young), and at 23 months(aged). Their FRTL-5 thyroid cells were harvested at cell passages less than 10(fresh) or more than 30 (aged). The expression of thyroid autoantigens, sodium-iodide symporter(NIS), TSH receptor (TSHR), TG and TPO, were examined by northern blot analysis. To evaluate the effects of iodide, 1mM of NaI was added to the medium for 24 hours, and following incubation the expressions of MHC class I and class II were also examined. RESULTS: The expressions of TPO were markedly increased in the aged rats, and those of TG were moderately. However, NIS and TSHR showed no differences in their expression levels between aged rats and young rats. In vitro, there were no differences in the expressions of TG or TPO, nor of NIS or TSHR, between aged cells and fresh cells. Neither did Iodide exhibit any influence on the expression of MHC molecules in aged cells or fresh cells. CONCLUSION: The expression levels of TPO and TG were increased in aged rats, which may partially explain the mechanism of increasing thyroid autoimmunity with age.
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