Influence of temperature of the perfusion solution on the kinetics of intestinal absorption of glucose in rats.

The kinetics of glucose intestinal absorption by rat jejunum at different solution temperatures, under single pass perfusion, has been studied in vivo. The non-passive component (active transport) has been measured as difference between control absorption and that in the presence of 5 X 10(-4) M phloridzin. Results at 37 degrees and 39 degrees C did not significantly differ, but at 32 degrees C a clear drop in total absorption, non-passive and passive components was observed. As temperature increases from 32 degrees to 37 degrees C the apparent value of Km for glucose transport decreases (from 21.2 mM to 13.1 mM), whilst the Vmax does not change, and the apparent mass-transfer coefficient for the passive component slightly increases. The results are discussed taking in consideration the effect of temperature on the diffusion across the unstirred water layers and on the active transport processes.