Premature expression of sucrase-isomaltase triggered by corticoid
-dependent changes in polyamine metabolism.
Nsi-Emvo, Edouard, Bruno Chaton, Charlotte Foltzer-Jourdainne,
Francine Gosse, and Francis Raul.
Institut de Recherche contre les Cancers de L'Appareil Digestif
(IRCAD), H[circumflex]opitaux Universitaires; and Institut National
de la Sant[acute]e et de la Recherche M[acute]edicale (INSERM)
Unit[acute]es 184 and 381, INSERM, Strasbourg, France
APStracts 2:0127G, 1995.
A possible link beetween the corticoid-elicited premature expression
of intestinal sucrase-isomaltase (SI) and endogenous changes in
polyamine metabolism was investigated in preweaned rats. Starvation
at postnatal day 12 caused a precocious expression of SI mRNA and
activity. A rapid upsurge of serum corticosterone was observed during
the first hour of isolation occuring in parrallel with a transient
enhancement of ornithine decarboxylase (ODC) expression and followed
by an increase in mucosal polyamine content. Administration of the
antiglucocorticoid RU 38486 completely prevented the starvation
evoked stimulation of ODC. The treatment of the sucklings with RU or
with [alpha]-difluoro-methylornithine (DFMO), a specific inhibitor of
ODC, dramatically reduced the amount of SI mRNA. When exogenous
hydrocortisone (HC) was administered to 12 day-old sucklings
nourished by their dam, an important accumulation of ODC mRNA was
observed, in the intestinal mucosa, 4h after treatment. Sucklings
receiving HC and treated concomitantly either with RU or DFMO
exhibited a reduced amount of ODC mRNA and a dramatic decline in both
SI mRNA and activity. All together these data support the view that
the premature induction of SI expression is dependent on changes in
ODC expression and polyamine metabolism that can be elicited either
by endogenous changes or by exogenously administered glucocorticoids.
Received 24 January 1995; accepted in final form 24 February
1995.
APS Manuscript Number G31-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.