Variation in branchial expression among insulin-like growth-factor binding proteins (igfbps) during Atlantic salmon smoltification and seawater exposure
Autor: | Chelsea K. Fujimoto, Björn Thrandur Björnsson, Stephen D. McCormick, Jason P. Breves, Silas K. Phipps-Costin, Ingibjörg Eir Einarsdottir |
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Rok vydání: | 2017 |
Předmět: |
Gills
0301 basic medicine Gill Atlantic salmon Salinity medicine.medical_specialty Physiology Acclimatization medicine.medical_treatment Salmo salar Smoltification Fresh Water Insulin-like growth factor-binding protein 03 medical and health sciences Insulin-like growth factor Osmoregulation 0302 clinical medicine Physiology (medical) Internal medicine medicine Animals Seawater Binding proteins Insulin-like growth-factor Salmo Growth hormone Ecosystem Hormone activity biology General Medicine biology.organism_classification Insulin-Like Growth Factor Binding Proteins 030104 developmental biology Endocrinology Liver biology.protein Cotransporter 030217 neurology & neurosurgery Research Article |
Zdroj: | BMC Physiology |
ISSN: | 1472-6793 |
Popis: | In preparation for migration from freshwater to marine habitats, Atlantic salmon (Salmo salar L.) undergo smoltification, a transformation that includes the acquisition of hyposmoregulatory capacity. The growth hormone (Gh)/insulin-like growth-factor (Igf) axis promotes the development of branchial ionoregulatory functions that underlie ion secretion. Igfs interact with a suite of Igf binding proteins (Igfbps) that modulate hormone activity. In Atlantic salmon smolts, igfbp4,−5a,−5b1,−5b2,−6b1 and−6b2 transcripts are highly expressed in gill. We measured mRNA levels of branchial and hepatic igfbps during smoltification (March, April, and May), desmoltification (July) and following seawater (SW) exposure in March and May. We also characterized parallel changes in a broad suite of osmoregulatory (branchial Na+/K+-ATPase (Nka) activity, Na + /K + /2Cl − cotransporter 1 (nkcc1) and cystic fibrosis transmembrane regulator 1 (cftr1) transcription) and endocrine (plasma Gh and Igf1) parameters. Indicative of smoltification, we observed increased branchial Nka activity, nkcc1 and cftr1 transcription in May. Branchial igfbp6b1 and -6b2 expression increased coincidentally with smoltification. Following a SW challenge in March, igfbp6b1 showed increased expression while igfbp6b2 exhibited diminished expression. igfbp5a,−5b1 and−5b2 mRNA levels did not change during smolting, but each had lower levels following a SW exposure in March. Salmonids express an especially large suite of igfbps. Our data suggest that dynamic expression of particular igfbps accompanies smoltification and SW challenges; thus, transcriptional control of igfbps may provide a mechanism for the local modulation of Igf activity in salmon gill. |
Databáze: | OpenAIRE |
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