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促甲状腺激素释放激素(TRH)是首先被提纯的下丘脑调节因子。其结构为(吡咯环)谷氨酸-组氨酸-脯氨酸-酰胺,并已人工合成。免疫分析法表明,许多种属的下丘脑TRH的分子结构相同。在哺乳动物中,其主要作用是促进垂体前叶的特殊细胞释放TSH。TRH在下丘脑内生成后经门脉系统进入垂体,作用于前叶有关细胞胞膜的特殊受体,激活腺甙酸环化酶,使环-磷酸腺甙增多,从而释放TSH。TRH也促进TSH的合成。对TRH的正常反应甲状腺功能正常者静注TRH15～30分钟后,血中TSH达高峰,1～4小时后渐回至基础水平。静注TRH剂量在15～500微克时,血中TSH成比例地增多,但若剂最超过500微克,其反应并无进一步增大。妇女在月经周期的滤泡期静注TRH后,血中TSH增高的反应比男性大。甲状腺功能正常的男性给予雌激素后对TRH的反应,文献报告很不一致。这可能与雌激素剂量不同有关。男性年龄较大者反应较小,女性则未有这种区别。长期使用大量皮质激素者对TRH的反应会减低,同时血中TSH的基础值减少。这可能是出于它作用于下丘脑,使TRH分泌减少。合成的TRH口服需用约50倍于静注的剂量才获得相同
Thyrotropin releasing hormone (TRH) is the hypothalamus regulator first purified. Its structure is (pyrrole ring) glutamic acid - histidine - proline - amide, and has been synthesized. Immunoassays show that the molecular structures of TRH in many species of the hypothalamus are the same. In mammals, its main role is to promote the release of TSH by specific cells in the anterior pituitary. TRH in the hypothalamus generated by the portal system into the pituitary, the role of the anterior lobe of the cell membrane-specific receptors, activating adenylyl cyclase, the ring - adenosine increased, thereby releasing TSH. TRH also promotes the synthesis of TSH. The normal response to TRH normal thyroid function intravenous TRH15 ~ 30 minutes after the peak TSH in blood, 1 to 4 hours after the gradual return to the basal level. Intravenous TRH doses of 15 to 500 micrograms, the blood TSH increased in proportion, but if the agent is more than 500 micrograms, the reaction did not further increase. Women in the menstrual cycle of follicular phase after TRH follicles, the blood TSH increased response than men. Thyroid function in men after estrogen response to TRH, the literature is very inconsistent report. This may be related to different estrogen doses. Older men responded less and women did not. Long-term use of large amounts of corticosteroids will reduce the response to TRH, while reducing the basal TSH value in blood. This may be due to its role in the hypothalamus, TRH secretion decreased. Synthetic TRH taken orally about 50 times the dose of intravenous access to get the same