Composition of the alkaline component of human gastric juice: effect of swallowed saliva and duodeno-gastric reflux.

Five patients (four with vitiligo and one with pernicious anaemia) were subjected to the histamine infusion test; there were achlorhydric while the remaining two secreted quite small amounts of acid. [Na+],[Cl-)and[alkali]were determined in the alkaline gastric juice samples (pH greater than 7.0). In order to assess the contribution of swallowed saliva the histamine test was done twice in each patient: (A) with precautions to prevent swallowing of saliva; and (B) with the patient allowed to swallow saliva freely. In each sample reflux of duodenal juice was estimated so that its contribution to the alkaline gastric aspirate could be assessed. Such reflex was absent in one patient, negligible in another, while in the remaining three patients the mean pyloric reflux amounted to no more than 8% of the observed volume. Swallowed saliva had diluting effect on [Na+] and [Cl-] but raised K+ concentration in the alkaline gastric aspirate. The comparison of alkaline gastric juice, free to an appreciable extent of salivary contamination, was shown to be relatively constant. The results are consistent with the two-component hypothesis of gastric secretion.