Zoeller R T, Wolff R S, Koller K J
Laboratory of Cell Biology, National Institute of Mental Health, Bethesda, Maryland 20892.
Mol Endocrinol. 1988 Mar;2(3):248-52. doi: 10.1210/mend-2-3-248.
Cellular levels of mRNA encoding pro TRH in the rostral paraventricular nucleus are reduced by thyroid hormones. To determine whether this regulatory effect of thyroid hormones requires a functional pituitary gland or, specifically, TSH, we examined the effect of T3 on proTRH mRNA in hypophysectomized, thyro-parathyroidectomized male rats with or without bovine TSH replacement. Hypophysectomy plus thyro-parathyroidectomy reduced serum T4 and TSH to undetectable levels in all animals and elevated TRH mRNA in the paraventricular nucleus over that of sham-operated animals. Eleven consecutive daily injections of T3 significantly reduced TRH mRNA levels in both sham controls and thyro-parathyroidectomized rats. However, 11 daily injections of bovine TSH (1 U/day) failed to alter the effect of T3 on TRH mRNA levels. These results demonstrate that the regulatory influence of thyroid hormones on the biosynthesis of TRH within the thyrotropic center of the brain is independent of the pituitary gland and of TSH.
甲状腺激素可降低延髓室旁核中编码促甲状腺激素释放激素原（proTRH）的mRNA的细胞水平。为了确定甲状腺激素的这种调节作用是否需要功能性垂体或特异性促甲状腺激素（TSH），我们研究了三碘甲状腺原氨酸（T3）对垂体切除、甲状腺-甲状旁腺切除的雄性大鼠（给予或未给予牛TSH替代）促甲状腺激素释放激素原（proTRH）mRNA的影响。垂体切除加甲状腺-甲状旁腺切除使所有动物的血清甲状腺素（T4）和促甲状腺激素（TSH）降至无法检测的水平，并使室旁核中的促甲状腺激素释放激素（TRH）mRNA高于假手术动物。连续11天每日注射T3可显著降低假手术对照组和甲状腺-甲状旁腺切除大鼠的促甲状腺激素释放激素（TRH）mRNA水平。然而，连续11天每日注射牛促甲状腺激素（1 U/天）未能改变T3对促甲状腺激素释放激素（TRH）mRNA水平的影响。这些结果表明，甲状腺激素对脑促甲状腺素中心内促甲状腺激素释放激素（TRH）生物合成的调节作用独立于垂体和促甲状腺激素（TSH）。
