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 an d systemic EGF and TGF have in intestinal absorption, elucidate a possible mechanism through which they exert their activity, and compare this respons e to that of a mixed meal only. Jejunal and ileal Thiry-Vella intestinal se gments were constructed in six dogs. Absorption was measured by infusing th e loops with a physiological electrolyte solution containing either 10 mmol or 50 mmol glucose and [C-14]PEG as the impermeant marker. In vivo studies show that the addition of either EGF or TGF resulted in increased absorpti on of Na+, Cl-, H2O, and glucose in the intestine. This response was signif icantly greater than that seen when giving a mixed meal alone. Luminal phlo ridzin, an inhibitor of the SGLT-1 transporter, inhibited intestinal absorp tion observed in response to EGF and TGF. In conclusion, these results sugg est 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.