Molecular and functional characterization of a urea transporter from the kidney of a short-finned pilot whale

Janech, Michael G.; Chen, Ruihua; Klein, Janet D.; Nowak, Mark W.; McFee, Wayne E.; Paul, Richard V.; Fitzgibbon, Wayne R.; Ploth, David W.

doi:10.1152/ajpregu.00323.2001

Cited by 16 publications

(15 citation statements)

References 46 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, the baleen whales showed higher concentrations of urea in both plasma and urine than the cattle and camels in this study, and other land mammals (Kaneko et al, 1997). The present study suggest that the cetaceans could maintain their body fluid to utilize urea in their kidney and that different actions of urea transporters between marine and terrestrial mammals, but there is only one report which investigated the function of urea transporters in cetaceans (Janech et al, 2002).…”

Section: Ureamentioning

confidence: 45%

Plasma and Urine Levels of Electrolytes, Urea and Steroid Hormones Involved in Osmoregulation of Cetaceans

Birukawa

Ando

Goto³

et al. 2005

Zoological Science

View full text Add to dashboard Cite

Cetaceans are well adapted to their hyperosmotic environment by properly developed osmoregulatory ability. A question here is how they regulate water and mineral balances in marine habitats. In the present study, we determined blood and urine levels of various chemicals involved in osmoregulation, compared them with those in artiodactyls, and characterized the values in the whales. Blood and urine samples obtained from baleen whales of common minke (Balaenoptera acutorostrata), sei (B. borealis), and Bryde's whales (B. brydei), and toothed whales of sperm whales (Physeter macrocephalus) were analyzed for osmolality, major electrolytes, urea, steroid hormones and glucose. The urine osmolality and Na + concentrations in the cetaceans were much higher than those in the cattle. Furthermore, the cetaceans had 5 to 11-fold urea in plasma than the cattle, and 2 to 4-fold urea in urine.There were no significant difference in the plasma concentrations of corticosteroids between the cetaceans and the cattle. The present results indicate that the osmoregulatory parameters seem to be not affected by the reproductive stage and sex steroid hormones. The concentrations of urea in plasma and urine of the baleen whales were higher than those of the sperm whales, indicating a possibility that their osmoregulatory mechanisms may be correlated to their feeding habits. The present results suggest that cetaceans have unique osmoregulatory mechanisms by which they excrete strongly hypertonic urine to maintain fluid homeostasis in marine habitats.

show abstract

Section: Ureamentioning

confidence: 45%

Plasma and Urine Levels of Electrolytes, Urea and Steroid Hormones Involved in Osmoregulation of Cetaceans

Birukawa

Ando

Goto³

et al. 2005

Zoological Science

View full text Add to dashboard Cite

show abstract

“…porter cDNAs that are most homologous to UT-A2 have been cloned from frog, elasmobranch, eel, gulf toadfish, Lake Migadi tilapia, and pilot whale (47)(48)(49)(50)(51)(52)(53). A detailed discussion of these urea transporters is beyond the scope of this review, and the reader is referred to the original citations for more information about them.…”

Section: The Ut-a Genementioning

confidence: 99%

Molecular Approaches to Urea Transporters

Sands¹

2002

Journal of the American Society of Nephrology

View full text Add to dashboard Cite

Abstract. Urea plays a critical role in the urine-concentrating mechanism in the inner medulla. Physiologic data provided evidence that urea transport in red blood cells and kidney inner medulla was mediated by specific urea transporter proteins. Molecular approaches during the past decade resulted in the cloning of two gene families for facilitated urea transporters, UT-A and UT-B, encoding several urea transporter cDNA isoforms in humans, rodents, and several nonmammalian species. Polyclonal antibodies have been generated to the cloned urea transporter proteins, and the use of these antibodies in integrative animal studies has resulted in several novel findings, including: (1) the surprising finding that UT-A1 protein abundance and urea transport are increased in the inner medulla during conditions in which urine concentrating ability is reduced; (2) vasopressin increases UT-A1 phosphorylation in rat inner medullary collecting duct; (3) UT-A protein abundance is upregulated in uremia in both liver and heart; and (4) UT-B is expressed in many nonrenal tissues and endothelial cells. This review will summarize the knowledge gained from using molecular approaches to perform integrative studies into urea transporter protein regulation, both in normal animals and in animal models of human diseases, including studies of uremic rats in which urea transporter protein is upregulated in liver and heart.

show abstract

“…A cDNA orthologue (UT-C) with relatively low sequence identity (35%) to the UT-As has been identified in eel kidney (Mistry et al, 2005). UT-A urea transporters have been shown to facilitate diffusive urea transport when expressed in Xenopus laevis oocytes (Smith and Wright, 1999;Fenton et al, 2000;Walsh et al, 2000;Walsh et al, 2001a;Shayakul et al, 2001;Janech et al, 2002;Stewart et al, 2006;MacIver et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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

Hung

Gálvez

et al. 2009

Journal of Experimental Biology

View full text Add to dashboard Cite

SUMMARYThe full-length cDNA sequence of a putative urea transporter (lfUT) of the facilitated diffusion UT-A type has been cloned from the African lungfish Protopterus annectens. The lfUT cDNA is 1990 bp in length and its open reading frame encodes a 409 amino acid long protein, with a calculated molecular mass of 44,723 Da. The sequence is closest to those of amphibians (~65% amino acid homology), followed by mammals and elasmobranchs (~60%), and then teleosts (~50%). lfUT was clearly expressed in gill, kidney, liver, skeletal muscle and skin. Upon re-immersion in water after 33 days of air exposure ('terrestrialization'), lungfish exhibited a massive rise in urea-N excretion which peaked at 12-30 h with rates of 2000-5000 μmol-N kg -1 h -1 (versus normal aquatic rates of <130 μmol-N kg -1 h -1) and persisted until 70 h. This appears to occur mainly through the skin. Total 'excess' urea-N excretion amounted to ~81,000-91,000 μmol-N kg -1 over 3 days. By real-time PCR, there was no difference in lfUT expression in the ventral abdominal skin between aquatic ammoniotelic controls and terrestrialized lungfish immediately after return to water (0 h), and no elevation of urea-N excretion at this time. However, skin biopsies revealed a significant 2.55-fold elevation of lfUT expression at 14 h, coincident with peak urea-N excretion. At 48 h, there was no longer any significant difference in lfUT mRNA levels from those at 0 and 14 h, or from aquatic fed controls. In accordance with earlier studies, which identified elevated urea-N excretion via the skin of P. dolloi with pharmacology typical of UT-A carriers, these results argue that transcriptional activation of a facilitated diffusion type urea transporter (lfUT) occurs in the skin during re-immersion. This serves to clear the body burden of urea-N accumulated during terrestrialization.

show abstract

Molecular and functional characterization of a urea transporter from the kidney of a short-finned pilot whale

Cited by 16 publications

References 46 publications

Plasma and Urine Levels of Electrolytes, Urea and Steroid Hormones Involved in Osmoregulation of Cetaceans

Plasma and Urine Levels of Electrolytes, Urea and Steroid Hormones Involved in Osmoregulation of Cetaceans

Molecular Approaches to Urea Transporters

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

Contact Info

Product

Resources

About