AJP - Gastrointestinal and Liver Physiology, Vol 246, Issue 6 649-G653, Copyright © 1984 by American Physiological Society
Polyamines in the response to intestinal obstruction
E. R. Seidel, M. K. Haddox and L. R. Johnson
The gastrointestinal mucosa immediately proximal to an intestinal
obstruction becomes hyperplastic. Since mucosa that is distal to an
obstruction atrophies, it appears that the adaptational response to
obstruction is regulated by local factors. The hypothesis tested in these
studies is that increased polyamine metabolism in the gut proximal to an
obstruction is a required local event in the hyperplastic process. Ligation
of either rat ileum or colon resulted within 66 h in a doubling of total
RNA, DNA, and protein content in the 2 cm of mucosa immediately proximal to
the tie. The trophic response was accompanied by an increase in primary
amine content of the intestinal chyme in the segment of gut under
investigation. These amines were not removed from intestinal chyme by 24 h
of lyophilization, suggesting that the more volatile short-carbon-chain
aliphatic amines were of limited importance. Subsequent studies focused on
polyamine metabolism. Ornithine decarboxylase (ODC) activity was increased
in the mucosa proximal to obstruction. In the ileum, ODC activity was
increased 10-fold over control values and in the colon about 2-fold.
Increased ODC activity was accompanied by corresponding increases in
mucosal polyamine content. Finally, treatment of rats with
difluoromethylornithine, a selective, irreversible inhibitor of ODC,
partially prevented the trophic response to intestinal obstruction.
