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Journal of Biomedicine and Biotechnology
Volume 2011 (2011), Article ID 510827, 14 pages
http://dx.doi.org/10.1155/2011/510827
Research Article

Loss of the NHE2 Na+/H+ Exchanger in Mice Results in Dilation of Folliculo-Stellate Cell Canaliculi

1Department of Environmental Health, University of Cincinnati, 3223 Eden Avenue, Cincinnati, OH 45267, USA
2Department of Biological Sciences, Northern Kentucky University, Nunn Drive, Highland Heights, KY 41099, USA
3Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0524, USA

Received 16 September 2010; Accepted 23 November 2010

Academic Editor: Monica Fedele

Copyright © 2011 Marian L. Miller et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Genetic ablation of the NHE2 Na+/H+ exchanger causes gastric achlorhydria, absorptive defects in kidney and colon, and low fertility. Here we show that NHE2 is expressed in the pituitary, with the highest mRNA expression in pars distalis and lower expression in pars intermedia. In pars distalis of NHE2-null mice, prominent cyst-like dilatations of folliculo-stellate (FS) cell canaliculi developed with age, and there were increased FS cell area, accumulation of lipid in FS cell cytoplasm, redundancies in FS cell basement membrane, and other changes. The expansion of the canaliculi indicates that NHE2 is a major absorptive Na+/H+ exchanger in the luminal membranes lining the extensive network of channels formed by FS cells, which may provide a means of intrapituitary communication. The results suggest that NHE2 contributes to homeostatic regulation of the volume and composition of the canalicular fluid and may counter the secretory activity of the CFTR Cl channel, which is known to be expressed in pituitary.