Molecular characterization and expression of urotensin II and its receptor in the flounder (Platichthys flesus) : a hormone system supporting body fluid homeostasis in euryhaline fish

Lu, Weiqun and Greenwood, Michael and Dow, Louise and Yuill, Janette and Worthington, John and Brierley, Matthew J and McCrohan, Catherine R and Riccardi, Daniela and Balment, Richard J (2006) Molecular characterization and expression of urotensin II and its receptor in the flounder (Platichthys flesus) : a hormone system supporting body fluid homeostasis in euryhaline fish. Clinical Endocrinology, 147 (8). pp. 3692-708. ISSN 0013-7227

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Abstract

Urotensin II (UII) is a potent vasoconstrictor in mammals, but the source of circulating UII remains unclear. Investigations of the caudal neurosecretory system (CNSS), considered the major source of UII in fish, alongside target tissue expression of UII receptor (UT), can provide valuable insights into this highly conserved regulatory system. We report UII gene characterization, expression of the first fish UT, and responses to salinity challenge in flounder. The 12-aa UII peptide shares 73% sequence identity with pig and human UII. Flounder UT receptor shares 56.7% identity with rat. Although the CNSS is the major site of UII expression, RT-PCR revealed expression of UII and UT in all tissues tested. Around 30-40% of large CNSS Dahlgren cells expressed UII, alone or in combination with urotensin I and/or corticotrophin releasing hormone. Immunolocalization of UT in osmoregulatory tissues (gill, kidney) was associated with vascular elements. There were no consistent differences in CNSS UII expression or plasma UII between seawater (SW)- and freshwater (FW)-adapted fish, although gill and kidney UT expression was lower in FW animals. After acute transfer from SW to FW, plasma UII and kidney and gill UT expression were reduced, whereas UT expression in kidney was increased after reverse transfer. UII appears to be more important to combat dehydration and salt-loading in SW than the hemodilution faced in FW. Potentially, altered target tissue sensitivity through changes in UT expression, is an important physiological controlling mechanism, not only relevant for migratory fish but also likely conserved in mammals.

Item Type:
Journal Article
Journal or Publication Title:
Clinical Endocrinology
Subjects:
?? adaptation, physiologicalamino acid sequenceanimalsbase sequencebody fluidsflounderfresh watergene expression regulationgene librarygillshomeostasisimmunohistochemistrykidneymolecular sequence datapituitary glandreceptors, g-protein-coupledreverse transcr ??
ID Code:
78958
Deposited By:
Deposited On:
04 Apr 2016 08:00
Refereed?:
Yes
Published?:
Published
Last Modified:
15 Jul 2024 15:56