Glucose translocation and metabolism in the rat jejunum perfused in once-through mode in vitro

Simultaneous once-through luminal and vascular perfusions with glucose of rat jejunum in vitro were used in an attempt to resolve conflicting reports on glucose metabolism in jejuna perfused in once-through mode in vivo and in recirculation mode in vitro. Results include: (a) respiration rates during each perfusion, (b) CO2 production from absorbed glucose, (c) absolute rates of glucose absorption from the lumen into the epithelium, (d) absolute rates of glucose translocation from lumen to vascular bed, (e) absolute rates of lactate excretion into the two perfusion media, (f) recoveries of absorbed glucose, (g) the distribution of radioactivity among translocated glucose and its metabolites. About 50% of the total lactate originates in the glucose extracted from the vascular medium during concomitant absorption and translocation of luminal glucose. The results suggest what further experiments need to be done. Results from recirculation perfusions in vitro cannot contest or confirm the results quoted from experiments conducted with once-through perfusions in vivo.