The effect of epidermal growth factor on the distribution of SGLT-1 in rabbit jejunum.
The effect of epidermal growth factor (EGF) on the cellular and villous distribution of the sugar transporter SGLT-1 was examined. New Zealand White rabbits (1 kg) were anesthetized, and two jejunal blind loops were isolated and exposed to either 0.9% saline or EGF (60 ng/mL saline), for 1 h. In separate experiments, tissue was harvested for brush border membrane vesicles (BBMV), microsomal membranes, or fixed for immunohistochemistry. SGLT-1 was measured in membrane fractions by Western immunoblot or localized along the villus-crypt axis by immunofluorescent microscopy. EGF increased BBMV SGLT-1 content compared with paired controls. EGF stimulation also induced a corresponding decrease in microsomal SGLT-1 levels and induced the expression of additional SGLT-1 immunoreactivity further down the villus axis. The findings suggest that EGF upregulates intestinal glucose transport by stimulating the translocation of SGLT-1 from an internal microsomal pool into the brush border, thereby recruiting more villus enterocytes into the glucose transporting population.
Chung
B M
BM
Gastrointestinal Research Group, University of Calgary, AB, Canada.
Wallace
L E
LE
Hardin
J A
JA
Gall
D G
DG
D000818:Animals; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D007583:Jejunum / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000032:analysis / Q000378:metabolism*; D008871:Microvilli / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009004:Monosaccharide Transport Proteins / Q000032:analysis / Q000378:metabolism*; D011817:Rabbits; D051269:Sodium-Glucose Transporter 1
D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D051269:Sodium-Glucose Transporter 1; D004815:Epidermal Growth Factor