Experimental Study on Secretion of Gastric Juice

Particularly on effects of plasma osmotic pressure

Abstract

The dogs equipped with gastric fistula received one of the test solutions by the intravenous administration at the body weight dose of 50ml/Kg. The test solutions were 0.9% NaCl, 5% glucose, 5% mannitol, 4.5% NaCl, 20% glucose and 20% mannitol. After the administration, gastric secretion of the dog was stimulated by histamine. Consecutive 15 minute gastric juice samples were collected, and for each samples, total acidity, free acidity, [Na⁺], [K⁺], [Cl^-], osmolarity of the gastric juice and that of the plasma were measured. The following results were obtained.
1) When dogs were loaded with isotonic solutions followed by the histamine stimulation, there were littel changes of [Cl^-] and the osmolarity of the gastric juice. But at the case of hypertonic solutions, rising of [Cl^-] and the osmolarity was observed.
2) Loadings with one of the three hypertonic solutions, which all caused the elevation of plasma osmolarity, differently influenced each other on the gastric secretion. Hypertonic solutions of NaCl and glucose, which are able to penetrate easily into the glandular cells, seemed to inhibit the rise of acidity at the histamine stimulation. However, this effect was never seen in the case of by pertonic mannitol solution. The same could be said about the acid output of gastric secretion.
3) When the plasma osmolarity was elevated, there were decreased volume and increased osmolarity of gastric juice in all cases studied. In the same experiments, deceased acidity of gastric juice was seen in the cases of NaCl and glucose.
4) Loading with 5% glucose solution promoted the gastric acid secretion.