Hernandez Arturo
Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, ME, United States.
Vitam Horm. 2018;106:473-500. doi: 10.1016/bs.vh.2017.06.005. Epub 2017 Jul 25.
Thyroid hormones (TH) exhibit pleiotropic regulatory effects on growth, development, and metabolism, and it is becoming increasingly apparent that the developing testis is an important target for them. Testicular development is highly dependent on TH status. Both hypo- and hyperthyroidism affect testis size and the proliferation and differentiation of Sertoli, Leydig, and germ cells, with consequences for steroidogenesis, spermatogenesis, and male fertility. These observations suggest that an appropriate content of TH and by implication TH action in the testis, whether the result of systemic hormonal levels or regulatory mechanisms at the local level, is critical for normal testicular and reproductive function. The available evidence indicates the presence in the developing testis of a number of transporters, deiodinases and receptors that could play a role in the timely delivery of TH action on testicular cells. These include the thyroid hormone receptor alpha (THRA), the MCT8 transporter, the TH-activating deiodinase DIO2, and the TH-inactivating deiodinase DIO3, all of which appear to modulate testicular TH economy and testis outcomes.
甲状腺激素（TH）对生长、发育和代谢具有多效性调节作用，并且越来越明显的是，发育中的睾丸是它们的一个重要靶器官。睾丸发育高度依赖于TH状态。甲状腺功能减退和亢进都会影响睾丸大小以及支持细胞、间质细胞和生殖细胞的增殖与分化，进而影响类固醇生成、精子发生和男性生育能力。这些观察结果表明，睾丸中TH的适当含量以及由此暗示的TH作用，无论是全身激素水平的结果还是局部水平的调节机制，对于正常的睾丸和生殖功能都至关重要。现有证据表明，发育中的睾丸中存在多种转运蛋白、脱碘酶和受体，它们可能在TH对睾丸细胞的及时作用传递中发挥作用。这些包括甲状腺激素受体α（THRA）、MCT8转运蛋白、TH激活脱碘酶DIO2和TH失活脱碘酶DIO3，所有这些似乎都调节睾丸TH代谢和睾丸结局。
