| Diurnal rhythms in hypothalamic/pituitary AVT synthesis and secretion in rainbow trout: Evidence for a circadian regulation. | |
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MedLine Citation:
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PMID: 21095192 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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Arginine vasotocin (AVT) and isotocin (IT) are two neurohypophysial peptide hormones for which a role in adaptation to environmental changes has been suggested in fish. In teleosts, there are only a few available studies about circadian changes of AVT and IT levels, and a role of those peptides in the circadian system has been mainly suggested on the basis of the role of the homologous hormone AVP in mammals. Herein, we evaluated the diurnal rhythms in plasma AVT, pituitary AVT and IT content and the hypothalamic pro-vasotocin (pro-VT) expression in rainbow trout kept under a natural photoperiod, as well as their persistence in constant darkness as a tool for defining circadian dependence. Trout kept under a natural light cycle showed clear diurnal rhythms in both circulating and pituitary AVT levels with peak values around the last hours of the light phase. Hypothalamic pro-VT mRNA was also rhythmically expressed with similar peak characteristics. These rhythms persisted in fish kept under constant darkness for nearly two consecutive days, although peaks were progressively attenuated and phase-advanced. An IT rhythm was also found in pituitary of the trout maintained under a natural photoperiod, but not in those kept under continuous darkness. These results suggest that rhythms of hypothalamic AVT synthesis might be regulated by endogenous circadian mechanisms, and these rhythms contribute to maintain a similar fluctuation in pituitary AVT secretion into the blood. A potential role for AVT in the circadian and seasonal time-keeping system of teleost fish, either as a component of the neural machinery that participates in the adaptation to cyclic environmental changes, or as a circadian/seasonal output signal, is also discussed. |
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Authors:
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Arnau Rodríguez-Illamola; Marcos A López Patiño; Jose L Soengas; Rosa M Ceinos; Jesús M Míguez |
Publication Detail:
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Type: Journal Article Date: 2010-11-21 |
Journal Detail:
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Title: General and comparative endocrinology Volume: 170 ISSN: 1095-6840 ISO Abbreviation: Gen. Comp. Endocrinol. Publication Date: 2011 Feb |
Date Detail:
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Created Date: 2011-01-17 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0370735 Medline TA: Gen Comp Endocrinol Country: United States |
Other Details:
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Languages: eng Pagination: 541-9 Citation Subset: IM |
Copyright Information:
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Copyright © 2010 Elsevier Inc. All rights reserved. |
Affiliation:
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Departamento de Biología Funcional y Ciencias de la Salud, Facultad de Biología, Universidad de Vigo, 36310 Vigo, Spain. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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