Intermedin/Adrenomedullin-2 inhibits growth hormone release from cultured, primary anterior pituitary cells.
Intermedin/Adrenomedullin-2 inhibits growth hormone release from cultured, primary anterior pituitary cells.
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DOI：
10.1210/en.2005-0949
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发表时间：
2006-02
期刊：
影响因子：
4.8
通讯作者：
Meghan M. Taylor;Sara L. Bagley;W. Samson
中科院分区：
文献类型：
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作者：
Meghan M. Taylor;Sara L. Bagley;W. Samson
间质(Intermedin，IMD)是肾上腺髓质素(AM)、降钙素基因相关肽(CGRP)、胰淀素(AMY)等多肽家族中的一个新成员。与AM和CGRP一样，IMD在循环中起到降低血压的作用，在大脑中起到抑制食物摄取的作用，这种作用可以通过激活已知的CGRP、AM或AMY受体来解释。由于AM、CGRP和AMY已被报道影响垂体前叶激素的分泌，我们研究了IMD对成年雄性大鼠分散的垂体前叶细胞GH、ACTH和催乳素分泌的影响。对数摩尔浓度从1.0 pm到100 nm的IMD未能显著改变这三种激素的基础释放。同样，IMD在体外也不能显著改变CRH刺激的ACTH或TRH刺激的催乳素的分泌。然而，IMD浓度依赖地抑制GHRH刺激的GH从这些细胞培养释放。IMD的作用虽然需要更高的浓度，但与生长抑素一样有效，而且与生长抑素一样，可能至少部分是通过减少cAMP积累来实现的。在AM-CGRP-AMY多肽家族的其他成员中，IMD的这些作用是不同的，这表明在垂体前叶存在一种新的、独特的IMD受体，并且IMD可能具有神经内分泌作用，与控制生长和新陈代谢的下丘脑机制相互作用。
Intermedin (IMD), a novel member of the adrenomedullin (AM), calcitonin gene-related peptide (CGRP), amylin (AMY) peptide family, has been reported to act promiscuously at all the known receptors for these peptides. Like AM and CGRP, IMD acts in the circulation to decrease blood pressure and in the brain to inhibit food intake, effects that could be explained by activation of the known CGRP, AM, or AMY receptors. Because AM, CGRP, and AMY have been reported to affect hormone secretion from the anterior pituitary gland, we examined the effects of IMD on GH, ACTH, and prolactin secretion from dispersed anterior pituitary cells harvested from adult male rats. IMD, in log molar concentrations ranging from 1.0 pm to 100 nm, failed to significantly alter basal release of the three hormones. Similarly, IMD failed to significantly alter CRH-stimulated ACTH or TRH-stimulated prolactin secretion in vitro. However, IMD concentration-dependently inhibited GHRH-stimulated GH release from these cell cultures. The effects of IMD, although requiring higher concentrations, were as efficacious as those of somatostatin and, like somatostatin, may be mediated, at least in part, by decreasing cAMP accumulation. These actions of IMD were not shared by other members of the AM-CGRP-AMY family of peptides, suggesting the presence of a novel, unique IMD receptor in the anterior pituitary gland and a potential neuroendocrine action of IMD to interact with the hypothalamic mechanisms controlling growth and metabolism.