Maximum acid output and position of peptic ulcers.

In a retrospective analysis of 2218 tests of gastric secretion 27% of patients with duodenal ulcers had an abnormal capacity to secrete acid. The abnormality was evident only in patients who had had symptoms for longer than three years, and was greatest in patients who had had symptoms for six to nine years. There was no significant difference between the capacity to secretic acid in patients who had symptoms of duodenal ulcer for less than three years and the capacity to secretic acid in normal controls. The tendency for the capacity to secrete acid to increase with duration of symptoms was also evident in patients with gastric ulcers. The positions in which ulcers were found were closely related to the maximum acid output (M.A.O.), and to the age of patients. The site of recurrent ulcers, after vagotomy and drainage, was also related to the M.A.O. after vagotomy. These influences of ageing and vagotomy on the site of ulcers can be attributed to their antecedent effect on the M.A.O. It is suggested that the capacity to secret acid alone is not responsible for the genesis of peptic ulcers but that it influences the position in which an ulcer may develop under the influence of an unknown ulcerogenic factor.