Preservation of intestinal gene expression during hibernation.
Carey, Hannah V., and Sandra L. Martin.
Department of Comparative Biosciences, School of Veterinary
Medicine, University of Wisconsin, Madison WI 53606 and Department of
Cellular and Structural Biology, University of Colorado Health
Sciences Center, Denver CO 80262
APStracts 3:0096G, 1996.
The role of luminal nutrients in regulating enterocyte gene expression
was studied in a natural model for long-term fasting, the hibernating
ground squirrel. Squirrels were studied during the active season and
during the hibernation season when they had not eaten for at least 12
weeks. The specific activities of sucrase, isomaltase and intestinal
alkaline phosphatase in jejunal brush border membranes were similar
in hibernating and active squirrels whereas aminooligopeptidase was
reduced in hibernators. Na+,K+-ATPase activity in jejunal mucosa was
unchanged by hibernation. Densitometric analysis of Western blots
showed that abundances of sucrase-isomaltase (SI),
aminooligopeptidase and the Na+/glucose transporter were similar in
the two activity states. Preservation of SI abundance in hibernation
was confirmed by immunocytochemistry. Slot blot analysis revealed no
differences in mRNA levels for these proteins between hibernating and
active squirrels. Enterocyte proliferation and migration rates were
greatly suppressed in torpid squirrels but increased immediately upon
re-warming during arousals. These results demonstrate the striking
constancy of enterocyte gene expression despite long-term fasting in
a hibernating mammal.
Received 15 November 1995; accepted in final form 24 April 1996.
APS Manuscript Number G490-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 May 96