Decreased hypothalamic growth hormone-releasing hormone content and pituitary responsiveness in hypothyroidism.
Decreased hypothalamic growth hormone-releasing hormone content and pituitary responsiveness in hypothyroidism.
复制标题
甲状腺功能减退症时下丘脑生长激素释放激素含量和垂体反应性降低。
DOI：
10.1172/jci112490
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Frohman,LA
中科院分区：
文献类型：
--
作者：
Katakami,H;Downs,TR;Frohman,LA
比较甲状腺切除术 (Tx) 和甲状腺素替代 (T4Rx) 对垂体生长激素 (GH) 分泌和下丘脑 GH 释放激素 (GRH) 浓度的影响，以明确甲状腺功能减退相关 GH 缺乏的机制。甲状腺切除大鼠表现出脉动 GH 分泌完全丧失，GRH 反应性和垂体 GH 含量大幅降低。 Tx 大鼠培养的垂体细胞表现出 GRH 敏感性降低、最大 GH 反应性降低以及细胞内环 AMP 对 GRH 的积累，而生长抑素 (SRIF) 对 GH 分泌的抑制作用增强。下丘脑GRH含量也显着降低。尽管垂体 GH 含量、GRH 和 SRIF 敏感性以及细胞内环 AMP 对 GRH 的反应仅部分恢复，但 T4Rx 完全恢复了下丘脑 GRH 含量和自发 GH 分泌。结果表明甲状腺功能减退症对 GH 分泌有多种影响，并表明 T4 除了恢复 GH 合成外，在维持正常 GH 分泌方面的关键作用与其对下丘脑 GRH 的影响有关。
The effects of thyroidectomy (Tx) and thyroxine replacement (T4Rx) on pituitary growth hormone (GH) secretion and hypothalamic GH-releasing hormone (GRH) concentration were compared to define the mechanism of hypothyroid-associated GH deficiency. Thyroidectomized rats exhibited a complete loss of pulsatile GH secretion with extensive reduction in GRH responsiveness and pituitary GH content. Cultured pituitary cells from Tx rats exhibited reduced GRH sensitivity, maximal GH responsiveness, and intracellular cyclic AMP accumulation to GRH, while somatostatin (SRIF) suppressive effects on GH secretion were increased. Hypothalamic GRH content was also markedly reduced. T4Rx completely restored hypothalamic GRH content and spontaneous GH secretion despite only partial recovery of pituitary GH content, GRH and SRIF sensitivity, and intracellular cyclic AMP response to GRH. The results indicate multiple effects of hypothyroidism on GH secretion and suggest that a critical role of T4 in maintaining normal GH secretion, in addition to restoring GH synthesis, is related to its effect on hypothalamic GRH.Images