Ahlquist J A, Franklyn J A, Ramsden D B, Sheppard M C
Department of Medicine, University of Birmingham, Queen Elizabeth Hospital.
J Mol Endocrinol. 1990 Aug;5(1):1-6. doi: 10.1677/jme.0.0050001.
Thyroid and steroid hormones act by similar mechanisms to influence gene expression in the anterior pituitary gland. The genes encoding the common alpha and TSH-beta glycoprotein subunits are known to be regulated by thyroid hormones; we report here the effects of androgen administration on levels of alpha and TSH-beta mRNA in pituitary cytoplasm in the euthyroid and hypothyroid female rat. Dihydrotestosterone (DHT) suppressed both alpha and TSH-beta mRNAs to levels lower than those found in untreated animals; a similar reduction was seen in hypothyroid animals treated with DHT. A biphasic response of TSH-beta mRNA was seen following administration of tri-iodothyronine (T3) to hypothyroid rats, with early stimulation followed by later inhibition; these changes were also evident after administration of T3 to androgen-treated animals, although mRNA levels were again suppressed. The effects of testosterone were similar to those of DHT. In contrast to the changes in mRNA levels, androgen administration did not lead to significant alterations in serum TSH concentrations or pituitary TSH content. These results indicate that, like thyroid hormones, androgens suppress both alpha and TSH-beta subunit mRNA levels in the female rat. Androgens, however, exert differential effects on TSH synthesis and release which contrast with those of thyroid hormones.
甲状腺激素和类固醇激素通过类似机制影响腺垂体中的基因表达。已知编码常见α和促甲状腺激素β糖蛋白亚基的基因受甲状腺激素调控；我们在此报告雄激素给药对甲状腺功能正常和甲状腺功能减退的雌性大鼠垂体细胞质中α和促甲状腺激素β mRNA水平的影响。双氢睾酮（DHT）将α和促甲状腺激素β mRNA均抑制至低于未处理动物的水平；在用DHT处理的甲状腺功能减退动物中也观察到类似的降低。对甲状腺功能减退的大鼠给予三碘甲状腺原氨酸（T3）后，促甲状腺激素β mRNA出现双相反应，早期刺激随后是后期抑制；在给予T3的雄激素处理动物中这些变化也很明显，尽管mRNA水平再次受到抑制。睾酮的作用与DHT相似。与mRNA水平的变化相反，雄激素给药并未导致血清促甲状腺激素浓度或垂体促甲状腺激素含量的显著改变。这些结果表明，与甲状腺激素一样，雄激素在雌性大鼠中抑制α和促甲状腺激素β亚基的mRNA水平。然而，雄激素对促甲状腺激素合成和释放的影响与甲状腺激素不同。
