Although the pathophysiology of peptic ulcer is complex and its etiology obscure, it seems clear that the presence of acid is essential to the development of this disease entity. While hypersecretion of hydrochloric acid is not invariably encountered clinically, it is significant that the highest levels of acid secretion ever recorded have been found in patients with the Zollinger-Ellison syndrome, certainly the most virulent form of the peptic ulcer diathesis extant.
In 1960, Card and Marks1 demonstrated that a direct relationship existed between the maximal secretory ability of the canine stomach and its parietal cell population. The subsequent communication of Polacek and Ellison2 in 1963, showing that the number of parietal cells was increased an average of threefold in patients with duodenal ulcer and eightfold in those with the Zollinger-Ellison syndrome, suggests that one of the basic mechanisms of peptic ulceration may be an overabundance of gastric acid
Ritchie WP, Delaney JD, Barzilai A, Lande AJ, Wangensteen OH. Experimental Alterations in Gastric Mucosal Cellular Population in Dogs. JAMA. 1966;197(2):113-117. doi:10.1001/jama.1966.03110020101032