Abstract
Acid secretion and O2 uptake were measured in frog gastric mucosae in vitro with ions customarily present in "physiological salt solution" varied in concentration or eliminated. Secretion occurs but at reduced rate when Na is 0.6 m[image] or less, and it is raised towards maximal when Na is 10 m[image]. Secretion occurs at 75% maximal when Li replaces Na. Neither added Ca nor Mg is necessary for secretion, but secretion is reversibly inhibited by 1 m[image] ethyl -enediaminetetraacetate. Secretion occurs when K is 0.3 m[image] but is maximal at 3 m[image]. It is 20% maximal when Cl is 0.2 m[image]or less and is unaffected by replacing Cl by Br, but it is reduced when Cl is replaced by I.