STUDIES OF THE SECRETION OF CORTICOTROPIN-RELEASING FACTOR AND ARGININE VASOPRESSIN INTO THE HYPOPHYSIAL-PORTAL CIRCULATION OF THE CONSCIOUS SHEEP .1. EFFECT OF AN AUDIOVISUAL STIMULUS AND INSULIN-INDUCED HYPOGLYCEMIA
STUDIES OF THE SECRETION OF CORTICOTROPIN-RELEASING FACTOR AND ARGININE VASOPRESSIN INTO THE HYPOPHYSIAL-PORTAL CIRCULATION OF THE CONSCIOUS SHEEP .1. EFFECT OF AN AUDIOVISUAL STIMULUS AND INSULIN-INDUCED HYPOGLYCEMIA
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DOI：
10.1159/000125141
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发表时间：
1989-04-01
影响因子：
4.1
通讯作者：
CLARKE, IJ
中科院分区：
文献类型：
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作者：
ENGLER, D;PHAM, T;CLARKE, IJ
本实验研究了清醒绵羊垂体门脉循环中促肾上腺皮质激素释放因子（CRF）和精氨酸加压素（AVP）的分泌特点。此外，我们检查了这两种下丘脑肽的分泌与三种前阿黑皮素肽分泌之间的时间关系，所述前阿黑皮素肽是促肾上腺皮质激素（ACTH）、ir-β-内啡肽和ir-α-黑素细胞刺激激素和皮质醇，并确定视听情绪刺激和胰岛素诱导的低血糖对整个下丘脑-垂体-肾上腺轴的影响。在基础状态下，CRF、AVP、三种前阿黑皮素肽和皮质醇的分泌本质上是脉动的，观察到三种CRF和AVP脉冲模式：CRF和AVP的一致增加、CRF的孤立上升和AVP的孤立增加。在5只动物中的4只中，3分钟视听应激（吠叫的狗）迅速增加了所有测量物质的血浆水平，尽管动物之间的影响幅度和持续时间明显不同。胰岛素诱导的低血糖显著增加AVP，并在较小程度上，CRF浓度在门静脉血浆中，从而改变CRF：AVP摩尔比。虽然垂体-肾上腺激活与下丘脑活动增加密切相关，但CRF/AVP分泌与ACTH分泌之间没有严格的1：1一致性。麻醉剂氯胺酮选择性地增加门静脉AVP浓度的水平，超过了在低血糖期间达到的水平，并迅速激活垂体肾上腺轴。我们得出以下结论：（1）CRF和AVP是由下丘脑以脉冲方式分泌的，（2）促肾上腺皮质激素释放激素（CRF）或促肾上腺皮质激素（AVP）的增加都能刺激ACTH的分泌，（3）应激时下丘脑CRF/AVP的释放与垂体ACTH分泌之间不存在严格的1：1一致性，这可能部分是由于下丘脑分泌了额外的促ACTH分泌素;（4）视听刺激和胰岛素的能力-诱导的低血糖增加CRF和AVP分泌表明室旁下丘脑可能被各种神经输入激活，（5）应激时CRF：AVP摩尔比的显著变化提示AVP可能是绵羊体内重要的ATH促分泌剂。
Studies were undertaken to characterize the secretion of corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) into the hypophysial-portal circulation of the conscious sheep. In addition, we examined the temporal relationship between the secretion of these two hypothalamic peptides and the secretion of three pro-opiomelanocortin peptides.sbd.adrenocorticotropic hormone (ACTH), ir-.beta.-endorphin, and ir-.alpha.-melanocyte-stimulationg hormone.sbd.and cortisol and determined the effects of an audiovisual emotional stimulus and insulin-induced hypoglycemia on the entire hypothalamic-pituitary-adrenal axis. In the basal state, the secretion of CRF, AVP, the three pro-opiomelanocortin peptides, and cortisol was pulsatile in nature, and three CRF and AVP pulse patterns were observed: a concordant increase in CRF and AVP, an isolated rise in CRF, and an isolated increase in AVP. In 4 of the 5 animals, a 3-min audiovisual stress (barking dog) rapidly increased the plasma levels of all the measured substances, although the magnitude and duration of the effect differed markedly between the animals. Insulin-induced hypoglycemia markedly increased AVP and, to a lesser extent, CRF concentrations in portal plasma and thereby altered the CRF:AVP molar ratio. Although pituitary-adrenal activation was closely correlated with the increased hypothalamic activity, a strict 1:1 concordance between CRF/AVP secretion and ACTH secretion was not seen. The anesthetic ketamine selectively increased portal AVP concentrations to levels which exceeded those attained during hypoglycemia and rapidly activated the pituitary-adrenal axis. We conclude the following: (1) CRF and AVP are secreted by the hypothalamus in a pulsatile fashion; (2) ACTH secretion can be stimulated by increases in either CRF or AVP; (3) the absence of a strict 1:1 concordance between hypothalamic CRF/AVP release and pituitary ACTH secretion during stess may be partly due to the release of additional hypothalamic ACTH secretagogues; (4) the ability of both audiovisual stimuli and insulin-induced hypoglycemia to augment CRF and AVP secretion indicates that the paraventricular hypothalamus may be activated by a variety of neural inputs, and (5) the marked alteration of the CRF:AVP molar ratio during stress suggests that AVP may be an important ATH secretogogue in vivo in the sheep.