EGF and TGF stimulate proabsorption of glucose and electrolytes by Na+/glucose cotransporter in awake canine model.
Growth factor-stimulated intestinal absorption has recently been described, but the cellular transport mechanisms mediating this response are unknown. The purposes of this study were to examine the effect that intraluminal and systemic EGF and TGF have in intestinal absorption, elucidate a possible mechanism through which they exert their activity, and compare this response to that of a mixed meal only. Jejunal and ileal Thiry-Vella intestinal segments were constructed in six dogs. Absorption was measured by infusing the loops with a physiological electrolyte solution containing either 10 mmol or 50 mmol glucose and [14C]PEG as the impermeant marker. In vivo studies show that the addition of either EGF or TGF resulted in increased absorption of Na+, Cl-, H2O, and glucose in the intestine. This response was significantly greater than that seen when giving a mixed meal alone. Luminal phloridzin, an inhibitor of the SGLT-1 transporter, inhibited intestinal absorption observed in response to EGF and TGF. In conclusion, these results suggest that growth factors are capable of up-regulating intestinal absorption of electrolytes and nutrients and, these effects are mediated, at least in part, by SGLT-1 pathways.
Rongione
A J
AJ
Department of Surgery, UCLA School of Medicine and Sepulveda VA Medical Center, Los Angeles, California 90024, USA.
Kusske
A M
AM
Newton
T R
TR
Ashley
S W
SW
Zinner
M J
MJ
Mcfadden
D W
DW
D000818:Animals; D004285:Dogs; D004573:Electrolytes / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D007082:Ileum / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010695:Phlorhizin / Q000494:pharmacology; D051269:Sodium-Glucose Transporter 1; D015291:Transforming Growth Factors / Q000494:pharmacology*
D004573:Electrolytes; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D051269:Sodium-Glucose Transporter 1; D004815:Epidermal Growth Factor; D015291:Transforming Growth Factors; D010695:Phlorhizin; D005947:Glucose