Pigment-dispersing activities and cortisol-releasing activities of melanocortins and their receptors in xanthophores and head kidneys of the goldfish Carassius auratus
Pigment-dispersing activities and cortisol-releasing activities of melanocortins and their receptors in xanthophores and head kidneys of the goldfish Carassius auratus
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DOI：
10.1016/j.ygcen.2011.06.019
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发表时间：
2011-09-15
影响因子：
2.7
通讯作者：
Takahashi, Akiyoshi
中科院分区：
文献类型：
--
作者：
Kobayashi, Yuki;Chiba, Hiroaki;Takahashi, Akiyoshi
黑皮质素受体（MCRs）的五种亚型介导α-黑素细胞刺激激素（α-MSH）和促肾上腺皮质激素（ACTH）的功能。在鱼类中，这些激素分别参与色素分散和皮质醇释放。α-MSH相关肽在某些鱼类中表现出ACTH样活性。我们最近发现，多个Mcr转录本在某些细胞类型的barfin比目鱼，这是有关的α-MSH活动的调节。在头肾中的α-MSH相关肽的皮质醇释放活性也观察到类似的结果。本研究采用金鱼为实验材料，探讨了多表达McRs的表达与α-MSH活性之间的关系。我们还确定了是否α-MSH相关肽在金鱼中表现出ACTH样活性。在黄色素细胞中观察到Mc 1 r的转录本，而不是其他亚型的转录本。在N-末端具有乙酰基的α-MSH被发现以剂量依赖性的方式在黄色素团中分散色素。发现该效力略大于脱乙酰基-α-MSH的效力。这些结果支持了我们的发现，即当单个Mcr亚型表达时，MCR对α-MSH具有更高的亲和力。另一方面，在头肾中观察到Mc 2 r的转录本，而不是其他亚型的转录本。ACTH（1-24）刺激的皮质醇释放呈剂量依赖性，而α-MSH相关肽无活性。因此，似乎MC 2 R也作为一个ACTH特异性受体在金鱼和α-MSH相关肽后释放皮质醇的协会是罕见的鱼类。(C)2011 Elsevier Inc. All rights reserved.
The five subtypes of melanocortin receptors (MCRs) mediate the functions of alpha-melanocyte-stimulating hormone (alpha-MSH) and adrenocorticotropic hormone (ACTH). In fish, these hormones are involved in pigment dispersion and cortisol release, respectively. alpha-MSH-related peptides exhibit ACTH-like activity in certain fishes. We recently found that multiple Mcr transcripts are expressed in some cell types in the barfin flounder, which is related to regulation of alpha-MSH activities. Similar results were also observed for the cortisol-releasing activity of alpha-MSH-related peptides in the head kidney. The present study was undertaken to assess relationship between the expression of multiply expressed Mcrs and alpha-MSH activities using goldfish. We also determined if alpha-MSH-related peptides exhibit ACTH-like activity in goldfish. The transcripts of Mc1r, but not those of other subtypes, were observed in xanthophores. alpha-MSH, which has an acetyl group at the N-terminus, was found to disperse pigment in a dose-dependent manner in xanthophores. This potency was found to be slightly greater than that of desacetyl-alpha-MSH. These results support our findings that MCR has a higher affinity for alpha-MSH when single Mcr subtype is expressed. On the other hand, transcripts of Mc2r, but not those of other subtypes, were observed in the head kidney. ACTH(1-24)-stimulated cortisol release was observed in a dose-dependent manner, while alpha-MSH-related peptides showed no activity. It therefore appears that MC2R also acts as an ACTH-specific receptor in goldfish and that association of alpha-MSH-related peptides upon release of cortisol is uncommon in fishes. (C) 2011 Elsevier Inc. All rights reserved.