Expression and function of intestinal hexose transporters after small intestinal denervation.
BACKGROUND
The role of neural regulation in expression and function of intestinal hexose transporters is unknown. The aim of this study is to determine the role of intestinal innervation in gene expression and function of the membrane hexose transporters, SGLT1, GLUT2, and GLUT5 in the enterocyte. We hypothesize that denervation of the small intestine decreases expression of hexose transporters, which leads to decreased glucose absorption.


METHODS
Six groups of Lewis rats were studied (n = 6 each) as follows: control, 1 week after sham laparotomy, 1 and 8 weeks after syngeneic (no immune rejection) orthotopic small-bowel transplantation (SBT) (SBT1 and SBT8) to induce complete extrinsic denervation, and 1 and 8 weeks after selective disruption of intrinsic neural continuity to jejunoileum by gut transection and reanastomosis (T/A1 and T/A8). All tissue was harvested between 8 AM and 10 AM. In duodenum, jejunum, and ileum, mucosal messenger RNA (mRNA) levels were quantitated by real-time polymerase chain reaction (PCR), protein by Western blotting, and transporter-mediated glucose absorption using the everted sleeve technique.


RESULTS
Across the 6 groups, the relative gene expression of hexose transporter mRNA and protein levels were unchanged, and no difference in transporter-mediated glucose uptake was evident in any region. The glucose transporter affinity (K(m)) and functional transporter levels (V(max)) calculated for duodenum and jejunum showed no difference among the 6 groups.


CONCLUSIONS
Baseline regulation of hexose transporter function is not mediated tonically by intrinsic or extrinsic neural continuity to the jejunoileum.
Iqbal
Corey W
CW
Department of Surgery, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Fatima
Javairiah
J
Duenes
Judith
J
Houghton
Scott G
SG
Kasparek
Michael S
MS
Sarr
Michael G
MG
D000818:Animals; D003714:Denervation; D004386:Duodenum / Q000294:innervation / Q000378:metabolism / Q000637:transplantation; D005786:Gene Expression Regulation / Q000502:physiology; D051273:Glucose Transporter Type 2 / Q000235:genetics / Q000378:metabolism*; D051296:Glucose Transporter Type 5 / Q000235:genetics / Q000378:metabolism*; D007082:Ileum / Q000294:innervation / Q000378:metabolism / Q000637:transplantation; D007421:Intestine, Small / Q000294:innervation* / Q000378:metabolism* / Q000637:transplantation; D007583:Jejunum / Q000294:innervation / Q000378:metabolism / Q000637:transplantation; D008297:Male; D023421:Models, Animal; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D051269:Sodium-Glucose Transporter 1 / Q000235:genetics / Q000378:metabolism*
D051273:Glucose Transporter Type 2; D051296:Glucose Transporter Type 5; D012333:RNA, Messenger; C495683:Slc2a2 protein, rat; C495727:Slc2a5 protein, rat; C495676:Slc5a1 protein, rat; D051269:Sodium-Glucose Transporter 1