Cell bicarbonate and chloride in the jejunum of rat and hamster incubated "in vitro"

1. In jejuna of rat and hamster incubated in vitro, the intracellular bicarbonate concentration has been calculated from direct measurements of pH and pc02 in scraped, diluted and homogenized mucosa Intracellular chloride concentrations have also been determined in the same intestinal tract of both animals. 2. Bicarbonate concentration appears to be much higher in the mucosal cell of the rat than in the hamster. Cell chloride concentration is higher in the mucosal cell of the hamster than in that of the rat. 3. From our data and from those of the literature concerning the profile of the electrical potential difference, we have evaluated the electrical and chemical driving forces acting on the two anions. 4. The results suggest that both bicarbonate and chloride can passively move from the cell across the serosal barrier, but they cannot move passively across the luminal pole of the mucosal cell.