AJP - Gastrointestinal and Liver Physiology, Vol 272, Issue 6 1530-G1539, Copyright © 1997 by American Physiological Society
GLUT2 and hexokinase control proximodistal gradient of intestinal glucose metabolism in the newborn pig
C. Cherbuy, B. Darcy-Vrillon, L. Posho, P. Vaugelade, M. T. Morel, F. Bernard, A. Leturque, L. Penicaud and P. H. Duee
Unite d'Ecologie et de Physiologie du Systeme Digestif, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
We have reported previously that a high glycolytic capacity develops soon
after birth in enterocytes isolated from suckling newborn pigs. In the
present work, we investigated whether such metabolic changes could affect
intestinal glucose utilization in vivo and examined possible variations in
glucose metabolism along the small intestine. Glucose utilization by
individual tissues was assessed using the 2-deoxyglucose technique. The
overall glucose utilization rate was doubled in suckling vs. fasting
2-day-old pigs because of significantly higher rates in all tissues
studied, except for the brain. In parallel, enterocytes were isolated from
the proximal, medium, or distal jejunoileum of newborn vs. 2-day-old pigs
and assessed for their capacity to utilize, transport, and phosphorylate
glucose. Intestinal glucose consumption accounted for approximately 15% of
glucose turnover rate in suckling vs. 8% in fasting pigs. Moreover, there
was a proximal-to-distal gradient of glucose utilization in the intestinal
mucosa of suckling pigs. Such a gradient was also evidenced on isolated
enterocytes. The stimulation of both hexokinase activity (HK2 isoform) and
basolateral glucose transporter (GLUT2), as observed in the proximal
jejunum, could account for such a site-specific effect of suckling.
