Effect of chronic cold exposure on the na dependent d-glucose
transport along the small intestine in ducklings.
Thomas, V[acute]eronique, B[acute]eatrice Pichon, Gabriel Crouzoulon,
and Herv[acute]e Barr[acute]e.
Laboratoire de Physiologie des R[acute]egulations
Energ[acute]etiques Cellulaires et Mol[acute]eculaires,
Universit[acute]e Claude Bernard, F-69622 Villeurbanne Cedex,
France
APStracts 3:0149R, 1996.
In conditions of chronic cold exposure, ducklings develop a non
shivering thermogenesis which requires a high energy expenditure.
Therefore, energy supply becomes essential to cold-acclimated
ducklings, which increase their intake of carbohydrate-rich food. The
aim of this work was to investigate the effect of cold acclimation on
the activity of the intestinal brush-border Na+/D-glucose
cotransport, which is the first major step controlling glucose
entrance into an organism. Cotransport activity was determined by
measuring D-glucose uptake in brush-border membrane vesicles isolated
from different parts of the small intestine of thermoneutral control
(25 degrees C) or cold-acclimated (4 degrees C) ducklings (Cairina
moschata). Two D-glucose transport sites were described in ducklings:
a high-affinity/low capacity site and a low-affinity/high capacity
site. The former was mainly located in the ileum and the latter in
the duodenum. These two transport sites were altered differently by
cold exposure. Major alterations occur in the ileum where 1) a
reduction in Km and Vmax of high-affinity site were observed, and 2)
the occurence of low-affinity site activity was noted in CA ducklings
while it was not detected in the TN group. Cold effect on high
-affinity site could be related to the changes in the ileal BBMV
lipids while cold effect on low-affinity site could be due, at least
in part, to the higher glycosyl content found in this segment. The
small intestine appears then able to react to cold exposure by
increasing both its mucosa mass in proximal segments and D-glucose
uptake capacity in ileum, to respond to the higher energy demand
induced by thermoregulatory requirements.
Received 1 August 1995; accepted in final form 6 March 1996.
APS Manuscript Number R487-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 23 April 96