DOUBLE LUMINAL AND VASCULAR PERFUSION OF CHICKEN JEJUNUM - STUDIES ON3-O-METHYL-D-GLUCOSE ABSORPTION

The aims of the present study were: (1) to set up a procedure for simu ltaneous vascular and luminal perfusion of the chicken jejunum; (2) to assess the transport capacity of the tissue under such conditions, an d (3) to study the effects of phloretin and theophylline, given throug h the vascular perfusate, on 3-O-methyl-D-glucose intestinal transport . The perfusion procedure described allowed the control of intestinal and vascular inflow rates and perfusion pressures so that these parame ters could be adjusted to physiological values. A perfluorochemical em ulsion was used as oxygen carrier for the vascular perfusate. The abso rptive function of the perfused tissue was assessed by means of its ab ility to transport 3-O-methyl-D-glucose. Furthermore, ultrastructure p reservation was evaluated by scanning and transmission electron micros copy. Results indicate that the perfused tissue kept its transport cap acity and morphology intact throughout the 120-min experimental period . Moreover, no hypersecretion was observed as indicated by the constan cy of perfusate volumes and perfusion pressures. Phloretin (1mM) or th eophylline (10 mM) added to the vascular perfusate markedly reduced th e transfer of 3-O-methyl-D-glucose from the enterocyte to the vascular fluid without affecting the uptake from the lumen. Our results sugges t that this preparation may be used as an alternative tool for the stu dy of intestinal absorption processes in avian species, particularly w hen complete examination is required of the efflux of substrates from the intestinal lumen to the vascular fluid.