Activity, abundance, distribution and expression of Na+/K+-ATPase in the salt glands of Crocodylus porosus following chronic saltwater acclimation

Cramp, Rebecca L., Hudson, Nicholas J. and Franklin, Craig E. (2010) Activity, abundance, distribution and expression of Na+/K+-ATPase in the salt glands of Crocodylus porosus following chronic saltwater acclimation. Journal of Experimental Biology, 213 8: 1301-1308.


Author Cramp, Rebecca L.
Hudson, Nicholas J.
Franklin, Craig E.
Title Activity, abundance, distribution and expression of Na+/K+-ATPase in the salt glands of Crocodylus porosus following chronic saltwater acclimation
Formatted title Activity, abundance, distribution and expression of Na+/K+-ATPase in the salt glands of Crocodylus porosus following chronic saltwater acclimation
Journal name Journal of Experimental Biology   Check publisher's open access policy
ISSN 0022-0949
1477-9145
Publication date 2010-04-15
Sub-type Article (original research)
DOI 10.1242/jeb.039305
Volume 213
Issue 8
Start page 1301
End page 1308
Total pages 8
Place of publication Cambridge, United Kindom
Publisher The Company of Biologists
Collection year 2011
Language eng
Subject C1
970106 Expanding Knowledge in the Biological Sciences
060699 Physiology not elsewhere classified
Formatted abstract Saltwater crocodiles, Crocodylus porosus, possess lingual salt glands which function to remove excess Na+ and Cl accumulated as a consequence of living in salt water. Little is known about the nature of ion transport systems in C. porosus salt glands and how these systems respond to an osmotic challenge. In the present study, we examined the distribution and regulation of the Na+/K+-ATPase (NKA) pump, specifically the {alpha}-(catalytic) subunit in the salt glands of C. porosus chronically acclimated (6 months) to freshwater (FW) or 70% seawater (SW). We hypothesised that in the SW-acclimated C. porosus there would be an up-regulation of the abundance, activity and gene expression of the NKA transporter. NKA was immunolocalised to the lateral and basal membrane of secretory cells. As predicted, the NKA {alpha}-subunit was 2-fold more abundant in SW-acclimated C. porosus salt glands. NKA gene expression was also elevated in the salt glands of SW- vs FW-acclimated crocodiles. There was no increase in the specific activity of NKA in SW-acclimated animals and the in vitro rate of oxygen consumption by salt gland slices from SW-acclimated animals was not significantly different from that of FW-acclimated animals. The proportion of tissue oxygen consumption rate attributable to NKA activity was not different between SW- and FW-acclimated animals (approximately 50%). These data suggest that either chronic SW acclimation does not affect NKA in crocodile salt glands in the same manner as seen in other models or crocodiles possess the capacity to moderate NKA activity following prolonged exposure to SW.
© 2010 by The Company of Biologists Ltd


Keyword Acclimation
Lingual salt gland
Osmoregulation
Reptile
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Biological Sciences Publications
 
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Created: Sun, 18 Apr 2010, 00:03:55 EST