Switching of Na+, K+-ATPase isoforms by salinity and prolactin in the gill of a cichlid fish

Tipsmark, Christian K.; Breves, Jason P.; Seale, André P.; Lerner, Darren T.; Hirano, Tetsuya; Grau, E. Gordon

doi:10.1530/joe-10-0495

Cited by 106 publications

(76 citation statements)

References 44 publications

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“…It has been shown that exposing tilapia to an osmotic challenge both increases the mRNA expression of appropriate ion transporting proteins and reduces the mRNA expression of ion transporting proteins that would be maladaptive (Hiroi et al, 2005Breves et al, 2010d;Tipsmark et al, 2011;Velan et al, 2011). NKA provides the driving force for ion transport within ionocytes.…”

Section: Discussionmentioning

confidence: 99%

“…The electrochemical gradient that drives transmembrane ion transport is provided by the basolaterally located ion pump, Na + /K + -ATPase (NKA) (Richards et al, 2003). In tilapia, salmonids and killifish, two isoforms of NKA, α1a and α1b, are differentially expressed in the gill, according to the salinity of the habitat (Richards et al, 2003;Madsen et al, 2009;McCormick et al, 2009;Tipsmark et al, 2011;Berdan and Fuller, 2012). In tilapia, NKAα1a expression predominates in FW-acclimated fish relative to SW-acclimated fish, while NKAα1b expression has been shown to be greater or unchanged in SW-acclimated fish when compared with FW-acclimated fish .…”

Section: Introductionmentioning

confidence: 99%

“…Extensive work has provided an understanding of how tilapia in FW and SW adapt to acute osmotic challenges (Dharmamba et al, 1967(Dharmamba et al, , 1973Ayson et al, 1993;Yada et al, 1994;Heijden et al, 1997;Sakamoto et al, 1997;Shepherd et al, 1999;Seale et al, 2002Seale et al, , 2006bSeale et al, , 2012bInokuchi et al, 2008Inokuchi et al, , 2009Ouattara et al, 2009;Breves et al, 2010bBreves et al, ,c,d, 2011Velan et al, 2011). While the effects of a salinity change on PRL cells and branchial mediators of ion transport are well documented in tilapia subjected to one-way transfers between two salinities, less is known about fish subjected to cyclic variations in salinity.…”

Section: Introductionmentioning

confidence: 99%

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The effects of acute salinity challenges on osmoregulation in Mozambique tilapia reared in a tidally changing salinity

Moorman

Lerner

Grau

et al. 2015

Journal of Experimental Biology

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This study characterizes the differences in osmoregulatory capacity among Mozambique tilapia, Oreochromis mossambicus, reared in freshwater (FW), in seawater (SW) or under tidally driven changes in salinity. This was addressed through the use of an abrupt exposure to a change in salinity. We measured changes in: (1) plasma osmolality and prolactin (PRL) levels; (2) pituitary expression of prolactin (PRL) and its receptors, PRLR1 and PRLR2; (3) branchial expression of PRLR1, PRLR2, Na− co-transporter (NKCC), α1a and α1b isoforms of Na + /K + -ATPase (NKA), cystic fibrosis transmembrane conductance regulator (CFTR), aquaporin 3 (AQP3) and Na + /H + exchanger 3 (NHE3). Mozambique tilapia reared in a tidal environment successfully adapted to SW while fish reared in FW did not survive a transfer to SW beyond the 6 h sampling. With the exception of CFTR, the change in the expression of ion pumps, transporters and channels was more gradual in fish transferred from tidally changing salinities to SW than in fish transferred from FW to SW. Upon transfer to SW, the increase in CFTR expression was more robust in tidal fish than in FW fish. Tidal and SW fish successfully adapted when transferred to FW. These results suggest that Mozambique tilapia reared in a tidally changing salinity, a condition that more closely represents their natural history, gain an adaptive advantage compared with fish reared in FW when facing a hyperosmotic challenge.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The effects of acute salinity challenges on osmoregulation in Mozambique tilapia reared in a tidally changing salinity

Moorman

Lerner

Grau

et al. 2015

Journal of Experimental Biology

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“…The mRNA expression of the following genes was then measured by real-time quantitative PCR: gill -atpa1a and atpa1b; liver -hsl, lepa, lepr, lipe, and lpl; and both gill and liver -glucose transporter 1 (glut1), glut4-l, and pyg. All primers, except atpa1a and atpa1b (see Tipsmark et al (2011)), were designed using ABI Primer Express (v3.0), and they are listed out in Supplementary Table 1, see section on supplementary data given at the end of this article, along with measurements of PCR efficiency calculated using the LinReg analysis of the log (fluorescence) amplification curves (Ramakers et al 2003). The mean efficiency range for all the qPCRs was 95.8-105.3%.…”

Section: Gene Expressionmentioning

confidence: 99%

Role for leptin in promoting glucose mobilization during acute hyperosmotic stress in teleost fishes

Baltzegar

Reading

Douros

et al. 2013

Journal of Endocrinology

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Osmoregulation is critical for survival in all vertebrates, yet the endocrine regulation of this metabolically expensive process is not fully understood. Specifically, the function of leptin in the regulation of energy expenditure in fishes, and among ectotherms, in general, remains unresolved. In this study, we examined the effects of acute salinity transfer (72 h) and the effects of leptin and cortisol on plasma metabolites and hepatic energy reserves in the euryhaline fish, the tilapia (Oreochromis mossambicus). Transfer to 2/3 seawater (23 ppt) significantly increased plasma glucose, amino acid, and lactate levels relative to those in the control fish. Plasma glucose levels were positively correlated with amino acid levels (R 2 Z0.614), but not with lactate levels. The mRNA expression of liver leptin A (lepa), leptin receptor (lepr), and hormone-sensitive and lipoprotein lipases (hsl and lpl) as well as triglyceride content increased during salinity transfer, but plasma free fatty acid and triglyceride levels remained unchanged. Both leptin and cortisol significantly increased plasma glucose levels in vivo, but only leptin decreased liver glycogen levels. Leptin decreased the expression of liver hsl and lpl mRNAs, whereas cortisol significantly increased the expression of these lipases. These findings suggest that hepatic glucose mobilization into the blood following an acute salinity challenge involves both glycogenolysis, induced by leptin, and subsequent gluconeogenesis of free amino acids. This is the first study to report that teleost leptin A has actions that are functionally distinct from those described in mammals acting as a potent hyperglycemic factor during osmotic stress, possibly in synergism with cortisol. These results suggest that the function of leptin may have diverged during the evolution of vertebrates, possibly reflecting differences in metabolic regulation between poikilotherms and homeotherms.

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“…Transcription studies indicate that there are salinity-dependent isoforms of the α-subunit expressed in the gills of salmonids and tilapia (Richards et al, 2003;Nilsen et al, 2007;Tipsmark et al, 2011). In a recent study on Atlantic salmon parr, we used specific antibodies to characterize two NKAα1 isoform proteins, NKAα1a and NKAα1b, which are the major isoforms expressed in freshwater and seawater, respectively (McCormick et al, 2009b).…”

Section: Introductionmentioning

confidence: 99%

Differential regulation of sodium–potassium pump isoforms during smolt development and seawater exposure of Atlantic salmon

McCormick

Regish²,

Christensen

et al. 2013

Journal of Experimental Biology

100

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SUMMARYFreshwater and seawater isoforms of the alpha subunit of Na + /K + -ATPase (NKA) have previously been identified in gill ionocytes of Atlantic salmon (Salmo salar). In the present study we examine the abundance and cellular localization of these isoforms during the parr-smolt transformation, a developmental process that is preparatory for seawater entry. The abundance of NKAα1a was lower in smolts than in parr, remained relatively constant during spring and decreased in summer. NKAα1b increased tenfold in smolts during spring, peaking in late April, coincident with downstream migration and increased salinity tolerance. NKAα1b increased a further twofold after seawater exposure of smolts, whereas NKAα1a decreased by 98%. The abundance of NKAα1b-positive, and NKAα1b and NKAα1a co-labeled ionocytes increased during smolt development, whereas the number of NKAα1a cells decreased. After seawater exposure of smolts, NKAα1b-positive ionocytes increased, NKAα1a-positive cells decreased, and co-labeled cells disappeared. Plasma growth hormone and cortisol increased during spring in smolts, but not in parr, peaking just prior to the highest levels of NKAα1b. The results indicate that the increase in the abundance of NKAα1b during smolt development is directly linked to the increase in salinity tolerance that occurs at this stage, but that significant changes also occur after seawater exposure. Spring increases in circulating levels of growth hormone and cortisol indicate that these hormones may be instrumental in upregulating NKAα1b during smolt development.

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Switching of Na+, K+-ATPase isoforms by salinity and prolactin in the gill of a cichlid fish

Cited by 106 publications

References 44 publications

The effects of acute salinity challenges on osmoregulation in Mozambique tilapia reared in a tidally changing salinity

The effects of acute salinity challenges on osmoregulation in Mozambique tilapia reared in a tidally changing salinity

Role for leptin in promoting glucose mobilization during acute hyperosmotic stress in teleost fishes

Differential regulation of sodium–potassium pump isoforms during smolt development and seawater exposure of Atlantic salmon

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