The Sex-Related Difference in Serum Thyrotropin Concentration Is Androgen Mediated*

Christianson, Dana; Roti, Elio; Vagenakis, Apostolos G.; Braverman, Lewis E.

doi:10.1210/endo-108-2-529

Cited by 68 publications

(37 citation statements)

References 22 publications

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“…Some previous reports indicate that estradiol might regulate thyroid function through a direct action on thyrocytes (34), apart from a possible effect on TSH secretion (35)(36)(37)(38). The administration of estradiol to ovariectomized and hypophysectomized rats leads to a higher thyroid radioiodide uptake (32,39), which supports the hypothesis of a direct effect of estrogen on the thyroid.…”

Section: Estrogensupporting

confidence: 71%

The importance of sodium/iodide symporter (NIS) for thyroid cancer management

Carvalho

Ferreira

2007

Arq Bras Endocrinol Metab

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The thyroid gland has the ability to uptake and concentrate iodide, which is a fundamental step in thyroid hormone biosynthesis. Radioiodine has been used as a diagnostic and therapeutic tool for several years. However, the studies related to the mechanisms of iodide transport were only possible after the cloning of the gene that encodes the sodium/iodide symporter (NIS). The studies about the regulation of NIS expression and the possibility of gene therapy with the aim of transferring NIS gene to cells that normally do not express the symporter have also become possible. In the majority of hypofunctioning thyroid nodules, both benign and malignant, NIS gene expression is maintained, but NIS protein is retained in the intracellular compartment. The expression of NIS in non-thyroid tumoral cells in vivo has been possible through the transfer of NIS gene under the control of tissue-specific promoters. Apart from its therapeutic use, NIS has also been used for the localization of metastases by scintigraphy or PET-scan with 124 I. In conclusion, NIS gene cloning led to an important development in the field of thyroid pathophysiology, and has also been fundamental to extend the use of radioiodine for the management of non-thyroid tumors. A glândula tireóide tem capacidade de captar e concentrar iodeto, etapa fundamental na biossíntese dos hormônios tireóideos. O uso de iodo radioativo para fins de diagnóstico e terapia das doenças da tireóide vem sendo feito há muitos anos. Entretanto, somente após a clonagem do gene que codifica o cotransportador de sódio/iodeto (NIS) houve aumento significativo dos estudos relacionados ao mecanismo de transporte de iodeto. Os estudos sobre a regulação da expressão do NIS e a possibilidade de terapia gênica visando à transferência do gene NIS para células que normalmente não expressam esse transportador, foram também viabilizados. Na maior parte dos nódulos tireóideos hipofuncionantes, tanto benignos quanto malignos, a expressão do gene do NIS está presente, mas a proteína NIS fica retida no compartimento intracelular. A transferência do gene usando-se promotores tecido-específicos possibilitou a expressão do NIS em células tumorais não-tireóideas in vivo. Além do seu uso terapêutico, o NIS também vem sendo usado para a localização de metástases tumorais através da cintilografia ou do PET-scan usando-se 124 I. Em conclusão, a clonagem do NIS possibilitou enorme avanço na área de fisiopatologia tireóidea e foi também fundamental para estender o uso do radioiodo para tumores não tireóideos.

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Section: Estrogensupporting

confidence: 71%

The importance of sodium/iodide symporter (NIS) for thyroid cancer management

Carvalho

Ferreira

2007

Arq Bras Endocrinol Metab

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“…There have been reports of decreased estrogen receptors in the brain and pituitary of aged female rodents (27,28). The significant decrease in the in vitro TSH release and intrapituitary TSH content caused by ovariectomy alone in old rats suggests that the ovary plays an important role in the regulation of the TSH response to TRH, even in old rats that lost their estrous cyclicity (29,30). This leads us to speculate that ovarian factors other than estrogen and Pg might be important, directly or indirectly, in the maintenance of TSH stores and TSH response to TRH in old rats.…”

Section: Discussionmentioning

confidence: 99%

“…This leads us to speculate that ovarian factors other than estrogen and Pg might be important, directly or indirectly, in the maintenance of TSH stores and TSH response to TRH in old rats. It is known that stroma cells continue to produce androgens after the end of folliculogenesis and testosterone has been reported to have stimulatory effects on TSH secretion (3,30). Chen and Walfish (31) showed a lower TSH response to TRH administered to old OVX rats compared to the adult OVX group, although the TRH response was not affected in intact old rats.…”

Section: Discussionmentioning

confidence: 99%

Effect of medroxyprogesterone acetate on thyrotropin secretion in adult and old female rats

Moreira

Borges

Lisboa

et al. 2000

Braz J Med Biol Res

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Steroid hormones have been implicated in the modulation of TSH secretion; however, there are few and controversial data regarding the effect of progesterone (Pg) on TSH secretion. Medroxyprogesterone acetate (MPA) is a synthetic a-hydroxyprogesterone analog that has been extensively employed in therapeutics for its Pg-like actions, but that also has some glucocorticoid and androgen activity. Both hormones have been shown to interfere with TSH secretion. The objective of the present study was to investigate the effects of MPA or Pg administration to ovariectomized (OVX) rats on in vivo and in vitro TSH release and pituitary TSH content. The treatment of adult OVX rats with MPA (0.25 mg/100 g body weight, sc, daily for 9 days) induced a significant (P<0.05) increase in the pituitary TSH content, which was not observed when the same treatment was used with a 10 times higher MPA dose or with Pg doses similar to those of MPA. Serum TSH was similar for all groups. MPA administered to OVX rats at the lower dose also had a stimulatory effect on the in vitro basal and TRH-induced TSH release. The in vitro basal and TRH-stimulated TSH release was not significantly affected by Pg treatment. Conversely, MPA had no effect on old OVX rats. However, in these old rats, ovariectomy alone significantly reduced (P<0.05) basal and TRH-stimulated TSH release in vitro, as well as pituitary TSH content. The results suggest that in adult, but not in old OVX rats, MPA but not Pg has a stimulatory effect on TSH stores and on the response to TRH in vitro.

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“…Additionally, it is well known that thyroid hormones are instrumental in positively regulating a-MHC expression, 25 and there is evidence that orchiectomy reduces thyroid hormone concentrations. 26 Exercise, however, has been shown to enhance thyroid hormone metabolism 27 and increase myocardial thyroid hormone receptor expression. 28 This exercise-induced thyroid hormone receptor upregulation has been shown to be associated with an increased expression of a-MHC 29 and provides a possible mechanism for cardioprotection in this context.…”

Section: Discussionmentioning

confidence: 99%