Hydrochloric acid. A trigger of cell proliferation in the esophagus of dogs.

The effect of a single instillation of acid and pepsin on the cell proliferation in the distal esophageal mucosa was investigated in four dogs. The doses of acid and pepsin used were lower than those provoking acute esophagitis and erosions. Using in vitro labeling with [3H]thymidine and autoradiography, the epithelial mitotic and DNA synthesis indices were determined at 0, 4, 8, 12, 16, 20, and 24 hr after instillation of saline, of, acid alone, or of acid with pepsin. Instillation of acid alone was followed, 16 hr later, by an increase (P less than 0.01) in DNA synthetic activity in the proliferative area. A mitotic peak (P less than 0.01) started from the 20th hour. After instillation of acid with pepsin in the same animals, a similar sequence of kinetic phenomena was observed, suggesting that the concentration of pepsin used did not potentiate the stimulating effect of acid on the cell proliferation in this epithelium. Our data indicate that hydrochloric acid stimulates the proliferative activity in the normal esophageal epithelium.