The secretory pattern of three stomach preparations in the rat.

1. In conscious rats provided with a gastric fistula, or a Pavlov pouch, or a Heidenhain pouch, the secretion of acid and pepsin was studied in the interdigestive state and in response to hog gastrin II. In Pavlov pouches and in Heidenhain pouches the responses to 2-deoxy-D-glucose and to food were established, as were also the responses to gastrin pentapeptide and methacholine in Heidenhain pouches.2. Interdigestive secretion of acid and pepsin is substantial in the gastric fistula and the Pavlov pouch preparation, whereas in the Heidenhain pouch acid secretion is low or scanty, and the ratio pepsin/acid output is higher than in the innervated preparations.3. Feeding evoked secretion of acid and pepsin in the Heidenhain and Pavlov pouches; the increase in pepsin secretion lasted much longer in the Heidenhain than in the Pavlov pouch.4. Methacholine, infused in a threshold dose, augmented the acid output in response to food in the Heidenhain pouch, but did not affect the pepsin output.5. Gastrin II (hog) evoked graded acid responses in the three stomach preparations, and the innervated preparations were more sensitive to gastrin II than the denervated one, whereas stimulation of pepsin secretion was apparent only in the Heidenhain pouch.6. Methacholine, on infusion, in the Heidenhain pouch, gave a maximal acid secretory response, greater than twice that obtained by gastrin, and produced strong stimulation of pepsin.7. Methacholine, infused in a threshold dose, accentuated the acid secretory response to graded doses of gastrin.8. 2-deoxy-D-glucose stimulated acid and pepsin secretion consistently in the Pavlov pouch, whereas in the Heidenhain pouch the response was scanty or absent.9. A large dose of gastrin pentapeptide injected intravenously while a background secretion was maintained by gastrin II, produced in the Heidenhain pouch triphasic changes in the sequence: stimulation, inhibition, stimulation.