Electrolyte Movement Across Canine Antral and Fundic Gastric Mucosa

Abstract

Isosmotic HCl solutions containing a nonabsorbable dilution indicator were instilled into vagally denervated canine antral and fundic pouches to study the comparative rates of electrolyte flux across the gastric surface epithelium from these two areas. Similar changes occurred in both pouches but hydrogen loss, sodium gain, and fluid entry were two to three times greater in the antrum; potassium entry was 10 to 12 times greater. Measurement of surface area of two antral, one mixed, and one fundic pouch suggest an even greater difference between the relative rates of electrolyte movement across these two types of gastric surface epithelium. Neither a cationic exchange of hydrogen for sodium nor dilution and neutralization by entering bicarbonate can alone account for the hydrogen ion loss. A combination of mechanisms, some as yet unknown, appears more likely. This increased antral permeability may be related to the physiological inhibition of gastrin release and the increased susceptibility of the antral mucosa to acid-peptic ulceration. The present data suggest that a significant portion of potassium appearing in gastric juice collected from the whole stomach enters through some component of the gastric mucosa other than parietal cells.