Effects of serosally added sugars on the transepithelial electrical properties of the perfused goldfish intestine.

1. A study has been made of the effect of serosally added sugars on the transmural potential difference and electrical resistance of the perfused goldfish intestine. 2. Addition of glucose at the serosal side resulted in a decrease of the transmural potential difference independent of the presence or absence of glucose at the mucosal side. The transepithelial resistance did not change. 3. The serosal glucose effect persisted in the presence of phlorizin at the mucosal side. 4. With the activity transported non-metabolized glucose analogue 3-oxy-methylglucose the same effects were observed as with glucose. 5. Replacement of NaCl by cholineCl, RbCl or LiCl at both sides of the intestine had a diminishing effect on the glucose evoked potentials and on the transepithelial conductance. 6. Phlorizin in concentrations lower than 10(-4) M, at the serosal side did not influence neither the mucosal nor the serosal glucose effects. 7. Ouabain at the serosal side inhibited the serosal glucose effect and decreased the transepithelial conductance. 8. The results support the concept that sugar transport at the serosal side of the epithelial cell has features in common with the sodium-dependent sugar transport mechanism at the mucosal side.