Effect of extracellular osmolality and ionic levels on pituitary prolactin release in euryhaline silver sea bream (Sparus sarba)

Kwong, Anna Ka-Yee; Ng, Andus H.Y.; Leung, Ling Yan; Man, Angel K.Y.; Woo, Norman Y.S.

doi:10.1016/j.ygcen.2008.10.024

Cited by 17 publications

(10 citation statements)

References 51 publications

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“…Our results confirmed the hyperosmotic role of PRL in S. aurata, in agreement with the reported for this hormone in the same species and in other teleost species (Manzon 2002;Sakamoto and McCormick 2006;Laiz-Carrión et al 2009;Vargas-Chacoff et al 2009b;Fuentes et al 2010;Link et al 2010). PRL cells increased in volume, occupying larger hypophyseal area, and showed bigger nuclear sizes and/or cytoplasmic features upon low osmolality challenge in both S. aurata and S. sarba, indicating an osmosensing capability of sea bream PRL cells (Mancera et al 1993b;Kwong et al 2009). In addition, ovine PRL treatment significantly decreased gill Na + , K + -ATPase activity while increased plasma osmolality and ions in juveniles of S. aurata acclimated for 24 h to seawater and brackish water (Mancera et al 2002).…”

Section: Prlsupporting

confidence: 91%

Acclimation to different environmental salinities induces molecular endocrine changes in the GH/IGF-I axis of juvenile gilthead sea bream (Sparus aurata L.)

2014

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To assess the role of the GH/IGF-I axis in osmotic acclimation of the gilthead seabream Sparus aurata, juvenile specimens were acclimated to four environmental salinities: hyposmotic (5 ‰), isosmotic (12 ‰) and hyperosmotic (40 and 55 ‰). The full-length cDNAs for both pituitary adenylate cyclase-activating peptide (PACAP) and prepro-somatostatin-I (PSS-I), the precursor for mature somatostatin-I (SS-I), were cloned. Hypothalamic PACAP and PSS-I, hypophyseal growth hormone (GH) and prolactin (PRL), and hepatic insulin-like growth factor-I (IGF-I) mRNA expression levels were analyzed in the four rearing salinities tested. PACAP and IGF-I mRNA values increased significantly in response to both 5 and 55 ‰ salinities, showing a U-shaped curve relationship with the basal level in the 40 ‰ group. Hypothalamic PSS-I expression increased strongly in the 55 ‰ environment. GH mRNA levels did not change in any of the tested environmental salinities. PRL mRNA maximum levels were encountered in the 5 and 12 ‰ environments, but significantly down-regulated in the 40 ‰. Plasma cortisol levels significantly increased in the 40 ‰ environment. These results are discussed in relation to the well-known high adaptability of Sparus aurata to different environmental salinities and the role of the GH/IGF-I axis in this process.

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Section: Prlsupporting

confidence: 91%

Acclimation to different environmental salinities induces molecular endocrine changes in the GH/IGF-I axis of juvenile gilthead sea bream (Sparus aurata L.)

2014

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“…Despite the lack of information on the molecular basis of PRL cell osmoreception, these studies suggest that stretch-activated ion channels that are permeable to calcium are responsible for the initiation of the signal transduction pathway that triggers PRL release. Recently, an increase in PRL release in response to a decrease in extracellular osmolality was also reported in silver sea bream Sparus sarba (17), suggesting that osmoreception in PRL cells may be widespread among teleost species. Therefore, clarification of the precise mechanism underlying the intrinsic osmosensitivity of PRL cells is important to a better understanding of osmoregulatory control of PRL in teleosts and may provide insight into the mechanisms governing osmoreception generally.…”

mentioning

confidence: 81%

Stretch-activated cation channel TRPV4 mediates hyposmotically induced prolactin release from prolactin cells of mozambique tilapia Oreochromis mossambicus

Watanabe

Seale

Grau

et al. 2012

American Journal of Physiology-Regulatory, Integrative and Comp

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In teleost fish, prolactin (PRL) is an important hormone for hyperosmoregulation. The release of PRL from the pituitary of Mozambique tilapia is stimulated by a decrease in extracellular osmolality. Previous studies have shown that hyposmotically induced PRL release is linked with cell volume changes, and that stretch-activated Ca(2+) channels are likely responsible for the initiation of the signal transduction for PRL release. In this study, we identified the stretch-activated Ca(2+) channel transient receptor potential vanilloid 4 (TRPV4) from the rostral pars distalis (RPD) of tilapia acclimated to freshwater (FW). TRPV4 transcripts were ubiquitously expressed in tilapia; the level of expression in RPDs of FW-acclimated fish was lower than that found in RPDs of seawater (SW)-acclimated fish. Immunohistochemical analysis of the pituitary revealed that TRPV4 is localized in the cell membrane of PRL cells of both FW and SW tilapia. A functional assay with CHO-K1 cells showed that tilapia TRPV4 responded to a decrease in extracellular osmolality, and that its function was suppressed by ruthenium red (RR) and activated by 4α-phorbol 12,13-didecanoate (4aPDD). Exposure of dissociated PRL cells from FW-acclimated tilapia to RR blocked hyposmolality induced PRL release. PRL release, on the other hand, was stimulated by 4aPDD. These results indicate that PRL release in response to physiologically relevant changes in extracellular osmolality is mediated by the osmotically sensitive TRPV4 cation channel.

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“…Further support for the importance of PRL in regulating HSP70 was provided as sea bream treated with the prolactin antagonist, bromocriptine exhibited increased hepatic HSP70 amounts (Deane et al 2000). As PRL is regarded as a hormone important during low salinity acclimation (Sakamoto and McCormick 2006) and it increases in sea bream upon exposure to dilute salinities (Kwong and Woo 2009) then it is plausible that it plays a key role in the regulation of HSP expression during low salinity exposure but this conjecture awaits further investigation.…”

Section: Importance Of Hormones On Fish Hsp Regulationmentioning

confidence: 99%

Advances and perspectives on the regulation and expression of piscine heat shock proteins

Deane

Woo

2010

Rev Fish Biol Fisheries

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The focus of this review is on the regulation and expression of heat shock proteins (HSPs), in fish. Within the past decade, molecular studies pertaining to the isolation and characterization of fish HSP genes have been rapidly expanding with many gene sequences from many fish species being reported. Most of the gene sequences presently available belong to the HSP70 family but genes encoding constitutive and inducible members of the HSP90 family have also been identified as well as genes encoding HSP60, HSP47 and small HSP families. Environmental stressors such as alterations in environmental salinity, disease and chemical exposure are known to alter HSP expression and the regulation of HSPs by hormones has received much attention recently. Heat shock proteins are known to play key roles during embryonic development and recent findings have defined their ontogenetic profiles following hatching. Finally, we are gradually starting to add to our understanding as to the transcriptional regulation of HSPs especially the role and importance of the heat shock factor (HSF).

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Effect of extracellular osmolality and ionic levels on pituitary prolactin release in euryhaline silver sea bream (Sparus sarba)

Cited by 17 publications

References 51 publications

Acclimation to different environmental salinities induces molecular endocrine changes in the GH/IGF-I axis of juvenile gilthead sea bream (Sparus aurata L.)

Acclimation to different environmental salinities induces molecular endocrine changes in the GH/IGF-I axis of juvenile gilthead sea bream (Sparus aurata L.)

Stretch-activated cation channel TRPV4 mediates hyposmotically induced prolactin release from prolactin cells of mozambique tilapia Oreochromis mossambicus

Advances and perspectives on the regulation and expression of piscine heat shock proteins

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