Gastric-acid output, pepsin output, and lean body mass in normal and duodenal-ulcer subjects.

Gastric-acid output bears a significant relationship to parietal cell mass and to lean body mass. The relationships of pepsin output to gastric-acid output and to lean body mass have been investigated in 13 normal subjects and 40 duodenal-ulcer patients. Peak pepsin output (P.P.O[I]) was stimulated by insulin-induced hypoglycaemia and the enzyme was assayed by Piper's method. Peak acid output to pentagastrin (P.A.O.[Pg] was obtained at a separate test. P.P.O.(I) correlated significantly with P.A.O.(Pg) in normal subjects (r equals 0-889, P less than 0-0001). P.P.O.(I) also showed good correlation with lean body mass (L.B.M.) (r equals 0-714, P less than 0-01), suggesting that P.P.O.(I) reflects peptic cell mass in normal subjects. In 40 duodenal-ulcer subjects there was no significant overall correlation of P.P.O.(I) with P.A.O(Pg) or with L.B.M. However, expressing the results as output of pepsin per milliequivalent of acid per kilogramme of lean body mass allowed separation of the ulcer patients into two groups whose ratios appeared to correlate with their symptomatic state at the time of testing: thus mean P.P.O(I) per meq. acid per kg. L.B.M. for duodenal-ulcer patients in relapse was significantly greater than the ratios for the patients in remission and for the normal group (P less than 0-001), suggesting either the presence of an increased sensitivity to insulin stimulation or a lack of pepsin inhibitor substance during a relapse of ulcer symptoms.