The Composition and Mechanism of Formation of Gastric Acid Secretion

Abstract

There is a close correlation in pure canine gastric juice between total chloride and the acidity of the gastric juice. In 152 specimens there is a strong negative correlation between neutral chloride and acid chloride. Extrapolation of line obtained by plotting neutral chloride as ordinate vs. acid chloride as abscissa intercepts the abscissa at a point corresponding to a concn. of 157-169 m[image] of HCl in all 6 sets of data treated statistically. On the basis of these findings a theory is developed that the fluid normally secreted by the parietal cells is a slightly hypertonic soln. of pure HC1 at concns. of 0.17 [image] and pH around 0.87. All other constituents of the gastric juice are produced by cells other than parietal cells or by transudation of intercellular fluid; and the lower acidity of normal gastric juice results from partial neutralization of parietal secretion by secretion of other cells, thus neutralization of HC1 of constant concn. will result in increased neutral chloride accounting for the marked negative correlation between these 2 entities. The hypothetical mechanism of parietal cell secretion involves the presence of a membrane in the cell which is permeable only to H2O, H+, and Cl (or other halide ions). In keeping osmotic work at a minimum, the H+ and Cl pass through this membrane in concn. approx. isotonic with cell contents. The Cl- is derived from NaCl and other neutral chlorides of the cell proto-plasm, the H from H2O; the alkali resulting from loss of H+ and Cl- is neutralized by cell buffers, and eventually eliminated by kidney.