AJP - Gastrointestinal and Liver Physiology, Vol 251, Issue 2 270-G274, Copyright © 1986 by American Physiological Society
Ornithine decarboxylase and mucosal growth in response to feeding
K. Tabata and L. R. Johnson
The purpose of this study was to examine the role of ornithine
decarboxylase (ODC) in the stimulation of the growth of gastrointestinal
mucosa following feeding. Rats were divided into five groups: 1) fasted for
2 days, 2) fasted for 2 days and refed for 2 days, 3) fasted for 2 days and
refed with the addition of 5% difluoromethylornithine (DFMO) to the
drinking water, 4) normally fed, and 5) normally fed plus 5% DFMO in the
drinking water. In general the results show a significant dissociation
between ODC activity and growth of gastrointestinal mucosa in response to
feeding. In the gastric mucosa, growth was inhibited by fasting and DFMO
and stimulated by feeding, but there were no significant changes in ODC
activity in any of the five groups. In the ileum ODC activity increased
dramatically in refed rats and was essentially eliminated in rats fed DFMO.
DFMO, however, had no effect on mucosal growth in fed rats and only
prevented part of the trophic response to refeeding. The results in the
colon were much the same as in the ileum, except that DFMO prevented even
less of the trophic response to refeeding, despite total inhibition of ODC.
These data suggest that polyamines necessary for growth of gastrointestinal
mucosa following feeding are not supplied by the rapid activation of
mucosal ornithine decarboxylase.
