Na+,k+ -atpase [alpha]1 and [beta]1 mrna and protein levels in the
rat small intestine in experimental ileitis.
Wild, G. E., and A. B. R. Thomson.
Cell and Molecular Biology Collaborative Network in
Gastrointestinal Physiology, Department of Medicine, Division of
Gastroenterology, McGill University, Montreal, Canada Department of
Anatomy and Cell Biology, McGill University, Montreal, Canada,
Nutrition and Metabolism Research Group, Division of
Gastroenterology, University of Alberta, Edmonton, Canada
APStracts 2:0107G, 1995.
The Na+,K+-ATPase plays a key role in the absorption of electrolytes,
water and nutrients from the small intestine. The expression of
Na+,K+-ATPase was examined in isolated enterocytes during the course
of the ileal inflammatory response elicited by intraluminal
administration of trinitrobenzene sulfonic (TNBS). The ileal
inflammatory response was characterized by a marked cellular
infiltrate, villous atrophy and crypt hyperplasia along with fibrosis
and smooth muscle hypertrophy. Peak levels of myeloperoxidase were
observed at day 7 and ileal mucosal injury was paralleled by
increases in ileal mucosal permeability. Ileal enterocytes were
harvested from day 3 to day 30 after the induction of ileitis.
Decreases in Na+,K+-ATPase functional activity were observed from day
3 to day 21 and were accompanied by corresponding decreases in
Na+,K+-ATPase pump abundance, [alpha]1 and [beta]1 protein expression
and mRNA abundance while Na+,K+-ATPase turnover and Km and Ki for Na+
and ouabain respectively were unaltered. Alterations in
transcriptional and posttranscriptional events may determine the
changes in Na+,K+-ATPase activity in this particular model.
Additionally observed increases in thymidine kinase and ornithine
decarboxylase activities appear to signify alterations in the state
of differentiation of the ileal epithelium and may determine the
phenotypic expression of enterocyte transporters and permeability in
the setting of inflammation.
Received 28 November 1994; accepted in final form 9 May 1995.
APS Manuscript Number G463-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 May 1995.