Chloride transport and acid secretion in stomach.

Chloride transport in isolated frog gastric mucosa is known to include major components due to active transport and exchange diffusion, and a minor component due to passive diffusion, but the sites responsible for moving Cl- within the mucosa have not been identified. The present study shows that the method used by Zerahn and others to measure transport pool yields an apparent Cl- pool which is close to the Cl- content of mucosal cells measured by chemical or radioactive means. Uptake of Cl- by the mucosal cells across the luminal surface in 2 min is rapid, constituting over one-half of the steady state cell content. The results suggest that much of this uptake occurs by exchange diffusion of Cl- at the secretory surface.