Maran R R M
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
Arch Androl. 2003 Sep-Oct;49(5):375-88. doi: 10.1080/01485010390204968.
Thyroid hormones are important for growth and development of many tissues. Altered thyroid hormone status causes testicular abnormalities. For instance, juvenile hypothyroidism/neonatal transient hypothyroidism induces macroorchidism, increases testicular cell number (Sertoli, Leydig, and germ cells) and daily sperm production. Triiodothyronine (T3) receptors have been identified in sperm, developing germ cells, Sertoli, Leydig, and peritubular cells. T3 stimulates Sertoli cell lactate secretion as well as mRNA expression of inhibin-alpha, androgen receptor, IGF-I, and IGFBP-4. It also inhibits Sertoli cell mRNA expression of Müllerian inhibiting substance (MIS), aromatase, estradiol receptor, and androgen binding protein (ABP) and ABP secretion. T3 directly increases Leydig cell LH receptor numbers and mRNA levels of steroidogenic enzymes and steroidogenic acute regulatory protein. It stimulates basal and LH-induced secretion of progesterone, testosterone, and estradiol by Leydig cells. Steroidogenic factor-1 acts as a mediator for T3-induced Leydig cell steroidogenesis. Although the role of T3 on sperm, germ, and peritubular cells has not yet been completely studied, it is clear that T3 directly regulates Sertoli and Leydig cell functions. Further studies are required to elucidate the direct effect of T3 on sperm, germ, and peritubular cells.
甲状腺激素对许多组织的生长和发育至关重要。甲状腺激素状态的改变会导致睾丸异常。例如，青少年甲状腺功能减退/新生儿短暂性甲状腺功能减退会诱发睾丸增大，增加睾丸细胞数量（支持细胞、间质细胞和生殖细胞）以及每日精子生成量。在精子、发育中的生殖细胞、支持细胞、间质细胞和睾丸周细胞中已鉴定出三碘甲状腺原氨酸（T3）受体。T3刺激支持细胞乳酸分泌以及抑制素α、雄激素受体、胰岛素样生长因子-I（IGF-I）和胰岛素样生长因子结合蛋白-4（IGFBP-4）的mRNA表达。它还抑制支持细胞中苗勒管抑制物质（MIS）、芳香化酶、雌二醇受体和雄激素结合蛋白（ABP）的mRNA表达以及ABP分泌。T3直接增加间质细胞促黄体生成素（LH）受体数量以及类固醇生成酶和类固醇生成急性调节蛋白的mRNA水平。它刺激间质细胞基础分泌以及LH诱导的孕酮、睾酮和雌二醇分泌。类固醇生成因子-1作为T3诱导的间质细胞类固醇生成的介质。尽管T3对精子、生殖细胞和睾丸周细胞的作用尚未完全研究清楚，但很明显T3直接调节支持细胞和间质细胞的功能。需要进一步研究以阐明T3对精子、生殖细胞和睾丸周细胞的直接作用。
