Inhibition of hydrochloric acid and pepsin secretion from gastric pouches by antral pouch acidification in sheep.

1. Secretion of acid and pepsin from separated pouches of the body of the abomasum was studied in sheep during perfusion of antral pouches with acid solutions. 2. Resting secretion of acid and pepsin was reduced by acidification of antral pouches to pH 2.7 or less. 3. Increases in the secretion of HCl and pepsin normally obtained on feeding were reduced or abolished by perfusion of antral pouches with solutions at pH 1.3--2.0. 4. Perfusion of antral pouches with acetylcholine at pH 2.5 failed to stimulate acid secretion as it did at a higher pH. 5. Pentagastrin stimulated acid and pepsin secretion during the inhibition of secretion produced by antral pouch acidification. 6. Increases in reticular motility occurred on antral pouch acidification with solutions of pH 1.1--1.3. 7. The contribution of antral pH in regulating abomasal acid secretion is discussed.