AJP - Gastrointestinal and Liver Physiology, Vol 258, Issue 6 942-G950, Copyright © 1990 by American Physiological Society
Gastric and duodenal mucosal ornithine decarboxylase and damage after corticosterone
J. Y. Wang and L. R. Johnson
Department of Physiology and Biophysics, University of Tennessee College of Medicine, Memphis 38163.
We recently found that stress increases gastric and duodenal ornithine
decarboxylase (ODC) activity and damages both tissues. The current study
investigated whether corticosterone induces ODC activity in gastric and
duodenal mucosa in rats and compared plasma corticosterone levels after
stress and treatment with corticosterone to determine whether this hormone
mediated the effects of stress on the mucosa. Rats were fasted 22 h, placed
in a restraint cage, and immersed in water to the xiphoid process for 6 h.
Stress markedly increased plasma corticosterone levels; the increase was
10.5 times control and lasted the duration of stress. The maximum increase
was observed 1 h after a single injection of corticosterone (5 mg/kg sc)
and represented 11.1 times control values. By 6 h, plasma corticosterone
had returned to normal levels. A single injection of corticosterone had no
effect on the gastric mucosa, but duodenal ODC was increased significantly
from 4 to 8 h after injection, peaking at 6 h. Histological examination
revealed no damage in either tissue. Administration of corticosterone three
times daily for 3 days dramatically elevated ODC activity and produced
significant microscopic damage. The surface epithelium of the stomach was
disrupted, with many surface cells shed, and most villi were absent from
the duodenal mucosa. Corticosterone also markedly decreased DNA and RNA
content of both tissues. Inhibition of ODC with
DL-alpha-difluoromethylornithine additionally decreased DNA, RNA, and
protein content, exacerbating the damage.(ABSTRACT TRUNCATED AT 250 WORDS)
