Thyroid Hormone Controls the Function of Hypothalamic GRF and SRIF Neurons

甲状腺激素控制下丘脑 GRF 和 SRIF 神经元的功能

• 批准号: 01044019
• 负责人: SUZUKI Mitsuo
• 金额: $ 5.5万
• 依托单位: Institute of Endocrinology, Gunma University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01044019/
• 关键词: GRF; SRIF; The arcuate nucleus; Periventricular nucleus; Thyroid hormone; Growth hormone; Fos-like protein; Thyroid hormone receptor

1. Neuronal networks of hypothalamic GRF and SRIF neurons in adult male rats and the role of SRIF in relation to growth hormone (GH) secretion.(1) GRF neurons in the arcuate nucleus (Arc) were connected to the vasolateral amygdala (BLA) via the stria terminals, while SRIF neurons in the periventricular nucleus (Pe), have connections to noradrenergic neurons in the brain stem. (2) Pe lesion markedly reduced SRIF content in the median eminence and blunted the sensitivity of pituitary GH cells to GRF stimulation. (3) SRIF pretreatment facilitated 2-fold GH release from the dispersed cells and also the increase in intracellular free Ca^<2+> ions by GRF stimulation.2. Effects of thyroid hormone on fos-like protein, thyroid hormone and SRIF receptors.(1) A number of fos-like immunoreactivity (IR) was examined in adult male rat brains and the IRs were found in the magnocellular and parvocellular regions of the paraventricular nucleus (mPVN & pPVN), anterior hypothalamus, lateral hypothalamus, … More and pyriform cortex. Six days after thyroidectomy (Tx), the number of fos-like IR cells increased 2-fold in PVN. (2) The mRNA of erbA alfa2, one of thyroid hormone recepror family was widely distributed in rat brains, particularly a dense localization was observed in the PVN, hypothalamic ventromedial nucleus, Arc, the hippocampus, medical amygdala, cerebral cortex, and pyriform cortex. After Tx, there was no significant change in the receptor gene expression in these regions, except in PVN, suggesting a negative feedback interrelation between PVN-TRH neural activity and circulating thyroid hormone concentration. (3) Changes in gene expression of GRF by Tx is still under investigation. But recently Downs et al. (1990) reported that Tx or hypophysectomy stimulates GRF gene expression, while thyroid hormone or GH replacement suppresses the increase, proposing that there is a negative feedback mechanism between GH and GRF gene expression. (4) SRIF receptors in rat brains were widely distributed in the regions such as the cerebral cortex, endopyriform nucleus, hippocampus, habenular nucleus and BLA. The number of SRIF receptor in these regions and PVN significantly increased after Pe lesion. However, Tx caused no change in the receptor number except an increase in BLA and thyroxine replacement could not restore the change. Less

1. 成年雄性大鼠下丘脑GRF和SRIF神经元的神经网络及SRIF在生长激素分泌中的作用(1)弓形核（Arc）的GRF神经元通过纹状末端与血管外侧杏仁核（BLA）相连，而脑室周围核（Pe）的SRIF神经元与脑干的去肾上腺素能神经元相连。(2) Pe损伤显著降低正中隆起的SRIF含量，减弱垂体GH细胞对GRF刺激的敏感性。(3) SRIF预处理可促进分散细胞释放2倍的GH，并可刺激细胞内游离Ca^<2+>离子。甲状腺激素对fos样蛋白、甲状腺激素和SRIF受体的影响。(1)在成年雄性大鼠脑内检测了多种fos样免疫反应性（IR），在室旁核（mPVN和pPVN）的大细胞区和旁细胞区、下丘脑前部区、下丘脑外侧区、More区和梨状皮质区均有发现。甲状腺切除术（Tx）后6天，PVN中fos样IR细胞数量增加2倍。(2)甲状腺激素受体家族erbaalfa2的mRNA在大鼠大脑中广泛分布，特别是在PVN、下丘脑腹内侧核、Arc、海马、医学杏仁核、大脑皮层和梨状皮质中都有密集的定位。Tx后，除PVN外，这些区域的受体基因表达均无显著变化，提示PVN- trh神经活性与循环甲状腺激素浓度之间存在负反馈关系。(3) Tx对GRF基因表达的影响仍在研究中。但最近Downs等（1990）报道Tx或垂体切除术刺激GRF基因表达，而甲状腺激素或GH替代抑制GRF基因表达，提出GH与GRF基因表达之间存在负反馈机制。(4)大鼠脑内SRIF受体广泛分布于大脑皮层、梨状内核、海马、缰核、BLA等区域。Pe病变后，这些区域和PVN的SRIF受体数量显著增加。然而，除了BLA增加外，Tx没有引起受体数量的变化，甲状腺素替代不能恢复这种变化。少

项目成果

鯉渕 典之 他: "甲状腺摘除はラット視床下部室傍核のフォス様蛋白を誘導する" Soc.Neurosci.Abst.1. 95 (1990)

Noriyuki Koibuchi 等人：“甲状腺切除术在大鼠下丘脑室旁核中诱导磷样蛋白”Soc.Neurosci.Abst.1 (1990)。

イスマイル・サブリ 鈴木 光雄: "甲状腺摘除のラット脳ソマトスタチン受容体の変化"

Ismail Sabri Mitsuo Suzuki：“甲状腺切除术后大鼠大脑中生长抑素受体的变化”

征矢 英昭・鈴木 光雄: "ソマトスタチン前処理はラット下垂体細胞の成長ホルモン分泌と遊離カルシウム上昇を増強する" Biochem.Biophys.Res.Commun.172. 276-281 (1990)

Hideaki Seiya 和 Mitsuo Suzuki：“生长抑素预处理增强大鼠垂体细胞中的生长激素分泌和游离钙升高”Biochem.Biophys.Res.Commun.176-281 (1990)。

Sabry, I., Kakegawa, T. and Suzuki, M.: "The effect of thyroidectomy on somatostatin binding stes in the rat brain : Autoradiographic study"

Sabry, I.、Kakekawa, T. 和 Suzuki, M.：“甲状腺切除术对大鼠大脑中生长抑素结合部位的影响：放射自显影研究”

Soya, H. and Suzuki, M. and Kato, M.: "Somatostatin preteatment facilitates GRF-induced GH release and increase in free calcium in pituitary cells" Biochem. Biophys. Res. Commun.172. 276-281 (1990)

Soya, H.、Suzuki, M. 和 Kato, M.：“生长抑素预处理促进 GRF 诱导的 GH 释放并增加垂体细胞中的游离钙”Biochem。