title: An avian sodium-hydrogen exchanger.
abstract: Intestinal sodium transporters, such as the Na+/H+ exchanger (NHE) are important for Na+ conservation in land birds. In mammals, at least five isoforms of the exchanger, NHEs 1-5, have been cloned, with NHE-1 occurring in epithelial basolateral and nonepithelial cell membranes and NHE-3 being restricted to epithelial apical/brush border membranes. We had demonstrated earlier that chicken intestinal brush border membranes possess NHE activity that functionally resembles mammalian NHE-3. In this study, we used mammalian NHE-1 and NHE-3 probes to examine if chicken enterocytes possess these transporters. Antisera against rat NHE-3 recognized a 97 kDa protein in chicken intestinal brush border membrane, while a NHE-3 cDNA probe failed to recognize any transcript. A NHE-1 antibody failed to recognize any protein in brush border or basolateral membrane, while a NHE-1 cDNA probe recognized a 3.9 kb transcript. Thus, there is more than one NHE isoform in chicken intestine, and our results suggest a novel avian NHE family.
authors.affiliation: Department of Physiology and Biophysics, University of Illinois at Chicago 60612, USA.
authors.forename: S G
authors.initials: SG
authors.lastname: Bhartur
authors.forename: C
authors.initials: C
authors.lastname: Bookstein
authors.forename: M W
authors.initials: MW
authors.lastname: Musch
authors.forename: R
authors.initials: R
authors.lastname: Boxer
authors.forename: E B
authors.initials: EB
authors.lastname: Chang
authors.forename: M C
authors.initials: MC
authors.lastname: Rao
mesh_terms: D000818:Animals; D002645:Chickens / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D015151:Immunoblotting; D007413:Intestinal Mucosa / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism; D008970:Molecular Weight; D051381:Rats; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; C000613387:Slc9a3 protein, rat; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1