Demonstration of bicarbonate secretion in rat duodenal brush border membrane vesicles

This study was designed to characterize the mechanisms available for bicarbonate transport across the apical membrane using rat duodenal brush border membrane vesicles (BBMVs), including the morphological findings. BBMVs were purified using a double Mg2+ precipitation technique. Electron microscopy of the final pellet showed only membrane material without contaminating organelles of cytoskeletal aggregates. BBMVs were enriched 15.1 +/- 3.2-fold in A-lp and 12.5 +/- 2.4-fold in LAP. The time course of 36Cl uptake into BBMVs demonstrated a good response curve and equilibrated to the intravesicular space over 120 min. In this present study, these BBMVs were purified and showed a stabilized structure. Therefore, these results suggest that this model was useful for studying HCO3- secretion and ulcer etiology.