Ions and water in the epithelial cells of XXXX descending colon.

@entity972 @entity1372 @entity95 @entity6478 @entity1877 @entity2507 @entity2865 @entity413
1. Isolated sheets of @entity95 descending colon epithelial cells stripped from their underlying muscle coats were incubated in chambers at 37 degrees C with oxygenated media, and their non-inulin space water, @entity1372 , @entity972 and @entity2865 contents were subsequently determined. 2. With @entity1372 Ringer bathing both surfaces, @entity6478 , 10(-4) M, decreased non-inulin space @entity1372 content by 76 mmol/kg dry wt. Ouabain, 10(-3) M, caused loss of non-inulin space @entity972 which was not completely compensated for by uptake of @entity1372 over 30 min incubation. @entity2865 and water, therefore, decreased. @entity6478 , 10(-4) M, inhibited but did not prevent this uptake of @entity1372 after ouabain. 3. Tissues exposed to @entity1372 -free @entity1877 Ringer rapidly exchanged non-inulin space @entity1372 for @entity1877 and, more slowly, lost @entity972 , @entity2865 and water. The equilibration of @entity1372 in the non-inulin space when @entity1372 Ringer was restored to the mucosal medium alone was largely @entity6478 -insensitive. For restoration of non-inulin space @entity972 to normal levels, @entity1372 was required in the serosal but not the mucosal medium. 4. Neither the absence of @entity413 nor the absence of @entity2865 from the mucosal medium affected the non-inulin space @entity1372 content when @entity1372 was restored to the mucosal medium bathing @entity1372 -depleted tissues. 5. It is argued that, whereas non-inulin space @entity972 and water contents are synonymous with their cellular values, only about one third of non-inulin space @entity1372 is cellular when @entity1372 Ringer bathes both surfaces, and the concentration of the @entity1372 within the cellular transport pool approximated 20 mmol/kg @entity2507 , consistent with estimates obtained from other techniques.
