Ahlquist J A, Franklyn J A, Ramsden D B, Sheppard M C
Department of Medicine, University of Birmingham, Queen Elizabeth Hospital, Edgbaston, U.K.
Mol Cell Endocrinol. 1989 Jun;64(1):55-61. doi: 10.1016/0303-7207(89)90064-6.
Glucocorticoid hormones suppress circulating concentrations of thyrotrophin (TSH), but their effect on synthesis of TSH in the pituitary gland is unclear. We have examined the influence of the glucocorticoid dexamethasone on serum TSH, pituitary TSH content and TSH beta- and alpha-subunit mRNA concentrations in pituitary cytoplasm in both the euthyroid and hypothyroid rat, and following triiodothyronine (T3) treatment in the hypothyroid rat. The rise in serum TSH in hypothyroidism was attenuated in animals treated with dexamethasone; in addition the suppression of serum TSH 6 h after T3 administration to hypothyroid rats was enhanced by dexamethasone. In contrast to the changes in serum TSH, pituitary TSH content was unaffected by dexamethasone. Furthermore dexamethasone had no significant effect on changes in pituitary cytoplasmic TSH beta- and alpha-subunit mRNA levels with thyroid status. These findings demonstrate that dexamethasone exerts differential effects on serum TSH levels and TSH biosynthesis which contrast with those of thyroid hormones.
糖皮质激素会抑制促甲状腺激素（TSH）的循环浓度，但其对垂体中TSH合成的影响尚不清楚。我们研究了糖皮质激素地塞米松对正常甲状腺大鼠和甲状腺功能减退大鼠血清TSH、垂体TSH含量以及垂体细胞质中TSHβ亚基和α亚基mRNA浓度的影响，以及甲状腺功能减退大鼠经三碘甲状腺原氨酸（T3）治疗后的影响。地塞米松治疗的动物中，甲状腺功能减退时血清TSH的升高受到抑制；此外，地塞米松增强了甲状腺功能减退大鼠给予T3后6小时血清TSH的抑制作用。与血清TSH的变化相反，垂体TSH含量不受地塞米松影响。此外，地塞米松对垂体细胞质中TSHβ亚基和α亚基mRNA水平随甲状腺状态的变化没有显著影响。这些发现表明，地塞米松对血清TSH水平和TSH生物合成具有不同的影响，这与甲状腺激素的影响形成对比。
