Relation between sodium concentration, electrical potential and transfer capacity of rat small intestine.

1. A study has been made of the effect of Na replacement in the incubation media on the hexose-dependent potential and the capacity of sacs of rat intestine to transfer fluid and galactose.2. Replacement of NaCl with mannitol or Tris Cl had little effect on the hexose-dependent potential, while replacement with LiCl and KCl had an inhibitory effect on the potential.3. Replacement with KCl, LiCl, mannitol and Tris Cl all reduced the capacity to transfer fluid and galactose, but the effects of Li and K replacement were greater than mannitol or Tris replacement.4. There is not a fixed relation between the magnitude of the potential and the amount of galactose transferred.