spacer gif spacer gif spacer gif spacer gif spacer gif
 QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online March 17, 2006
Journal of Experimental Biology 209, 1207-1216 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02123
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Konno, N.
Right arrow Articles by Uchiyama, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Konno, N.
Right arrow Articles by Uchiyama, M.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Effect of osmotic stress on expression of a putative facilitative urea transporter in the kidney and urinary bladder of the marine toad, Bufo marinus

Norifumi Konno1, Susumu Hyodo2, Kouhei Matsuda1 and Minoru Uchiyama1,*

1 Department of Biology, Faculty of Science, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
2 Laboratory of Physiology, Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo, 164-8639, Japan

* Author for correspondence (e-mail: uchiyama{at}sci.toyama-u.ac.jp)

Accepted 24 January 2006

Anuran amphibians accumulate a large amount of urea in their extracellular fluids to avoid a severe dehydration under dry and hyper-saline environments. To clarify the mechanisms of urea retention, we examined structure and distribution of the urea transporter (UT) in the kidney of the marine toad (Bufo marinus), and its expression in the kidney and urinary bladder following exposure to dry and hyper-saline conditions by means of cDNA cloning, semi-quantitative RT-PCR, immunoblot analysis and immunohistochemistry. The Bufo UT cDNA cloned from the kidney encodes a 390-amino-acid residue protein, which is 80% identical to Rana esculenta UT with the functional characteristics of a urea transporter. The Bufo UT mRNA was abundantly expressed in the kidney and urinary bladder, but not in the skin. In immunoblot analysis using a specific antibody raised against the Bufo UT, a 52 kDa protein similar to the glycosylated forms of mammalian UT-A2 (~55 kDa) was detected in extracts from plasma membrane fractions of the kidney and urinary bladder. When toads were acclimated to dry and hyper-saline environments for 7 days, UT mRNA expression was upregulated in the kidney and urinary bladder and there was an elevated plasma urea concentration and osmolality. Immunohistochemistry showed that the UT was specifically localized on the apical membrane of the early distal tubule, known to be the diluting segment, in the kidney and the epithelial cells of urinary bladder. Immunoreactive cells were not detected along the late distal tubule, the connecting tubule or the collecting duct in the kidney. The present findings suggest that the Bufo UT probably contributes to urea transport in the kidney and urinary bladder in response to hyperosmotic stresses such as body fluid hypertonicity and dehydration.

Key words: urea transporter (UT), kidney, diluting segment, Bufo marinus, osmoregulation


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:


Home page
J. Exp. Biol.Home page
N. Konno, S. Hyodo, Y. Yamaguchi, H. Kaiya, M. Miyazato, K. Matsuda, and M. Uchiyama
African lungfish, Protopterus annectens, possess an arginine vasotocin receptor homologous to the tetrapod V2-type receptor
J. Exp. Biol., July 15, 2009; 212(14): 2183 - 2193.
[Abstract] [Full Text] [PDF]


Home page
J. Exp. Biol.Home page
C. Y. C. Hung, F. Galvez, Y. K. Ip, and C. M. Wood
Increased gene expression of a facilitated diffusion urea transporter in the skin of the African lungfish (Protopterus annectens) during massively elevated post-terrestrialization urea excretion
J. Exp. Biol., April 15, 2009; 212(8): 1202 - 1211.
[Abstract] [Full Text] [PDF]


Home page
J. Exp. Biol.Home page
M. Uchiyama, R. Kikuchi, N. Konno, T. Wakasugi, and K. Matsuda
Localization and regulation of a facilitative urea transporter in the kidney of the red-eared slider turtle (Trachemys scripta elegans)
J. Exp. Biol., January 15, 2009; 212(2): 249 - 256.
[Abstract] [Full Text] [PDF]




© The Company of Biologists Ltd 2006