Constitutive expression of inducible nitric oxide synthase in the
mouse ileal mucosa.
Hoffman, Rosemary A., Guisheng Zhang, Natascha C. N[umlaut]ussler,
Susan L. Gleixner, Henri R. Ford, Richard L. Simmons, Simon C.
Watkins.
Departments of Surgery and Cell Biology and Physiology, University
of Pittsburgh, Pittsburgh, PA 15261; Department of Surgery,
Universitaetsklinikum Rudolf-Virchow, Humboldt University,
Augustenburger Platz 1, 13353 Berlin, Germany
APStracts 3:0190G, 1996.
It has been previously demonstrated that the inducible isoform of
nitric oxide synthase (iNOS) is present throughout the intestinal
tract in various inflammatory disease processes. Here we demonstrate
that, in fact, iNOS mRNA is present in the ileum, but not in the
jejunum or colon of normal mice. By western blot analysis, iNOS
protein is also detected in normal ileum, but not the normal jejunum.
However, by three hours post-injection of 0.5 mg/kg LPS, iNOS mRNA is
also detectable in the jejunum and colon. The enzyme message and
protein, localized immunohistochemically by in situ hybridization and
iNOS expression, is normally restricted to the villus epithelial
cells. The iNOS mRNA was also present in the ilea of mice with
defined intestinal flora (anaerobes only), germ-free mice, nude mice
and, to a lesser extent, in mice with severe combined
immunodeficiency (SCID). These results suggest that the constitutive
presence of iNOS in ileal epithelium indicates a role for this enzyme
in maintaining intestinal homeostasis.
Received 16 January 1996; accepted in final form 6 September
1996.
APS Manuscript Number G17-6.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 7 October 1996