Increased NHE2 expression in rat intestinal epithelium during ontogeny is transcriptionally mediated
Departments of Pediatrics and Physiology, Steele Memorial Children's Research Center, University of Arizona Health Sciences Center, Tucson, Arizona 85724 We have previously described changes in intestinal brush-border membrane vesicle (BBMV) Na + /H + exchange activity and characterized Na + /H...
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Published in | American Journal of Physiology: Cell Physiology Vol. 275; no. 4; pp. C1143 - C1150 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.10.1998
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Subjects | |
Online Access | Get full text |
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Summary: | Departments of Pediatrics and Physiology, Steele Memorial
Children's Research Center, University of Arizona Health Sciences
Center, Tucson, Arizona 85724
We have previously described changes in intestinal brush-border
membrane vesicle (BBMV)
Na + /H +
exchange activity and characterized
Na + /H +
exchanger (NHE3) expression during rat ontogeny. The current studies
were designed to investigate developmental changes in NHE2 expression
in rat intestine. In previous studies, pH-dependent uptake of
Na + in jejunal BBMV utilizing
HOE-694 inhibition demonstrated that NHE2 functional protein levels
were lowest in 2-wk-old rats, higher in 3-wk-old and adult rats, and
highest in 6-wk-old rats [Collins et al. Am. J. Physiol . 273 ( Cell
Physiol. 42): C1937-C1946, 1997]. In the
current investigation, Northern blot analyses showed that NHE2 mRNA
levels in the jejunum were similar in 6-wk-old, adult, and 3-wk-old
rats and three- to fivefold lower in 2-wk-old rats. In situ
hybridization of 2- and 6-wk-old rat intestine with NHE2-specific probes confirmed Northern blot observations. Polyclonal antibodies were
developed against an NHE2-specific peptide from amino acids 652-661. Western blots with NHE2 antiserum showed that the
intensity of a specific 90-kDa band was lowest in 2-wk-old animals and
four- to sixfold higher in 3- and 6-wk-old and adult animals.
Immunohistochemical analysis showed specific staining of NHE2 antiserum
to only the apical intestinal membrane. Furthermore, nuclear run-on
analyses showed a 1.7-fold higher NHE2 transcription rate in 6-wk-old
rats than in 2-wk-old rats. Overall, the current data suggest that increases in NHE2 expression upon weaning are mediated by increased gene transcription.
rat intestinal development; sodium/hydrogen exchanger; brush-border
membrane; transcription rate analysis; jejunum |
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ISSN: | 0363-6143 0002-9513 1522-1563 |
DOI: | 10.1152/ajpcell.1998.275.4.c1143 |