Short circuit current and total conductance measurements on rat ileum.

1. Short circuit current and total conductance measurements were made on preparations of rat terminal ileum, using either the intact tissue or the isolated epithelium.2. The effects of D-glucose, 3-O-methyl-D-glucose, and 3-deoxy-3-fluor-D-glucose, added in suitable concentrations to the external bathing medium, were studied.3. An increase in both short circuit current and total conductance was detected when these sugars were used. It was possible to determine a linear relationship between the two variables and to study the kinetics of the interaction of glucose and 3-O-methyl-D-glucose with the sodium sugar carrier by using increasing concentrations of these substances.4. The increases in short circuit current and total conductance were also verified in isolated epithelium.5. Phlorizin, or the withdrawal of glucose, reversed the increase in short circuit current, but the total conductance remained unchanged.6. Increasing concentrations of 2-deoxy-D-glucose added to the mucosal bathing medium caused a decrease in short circuit current without changing the total conductance, either in preparations of intact ileum or in isolated epithelium.7. The meaning of these variations in the electrical parameters of the preparations is discussed.