Increased sensitivity to stimulation of acid secretion by pentagastrin in duodenal ulcer.

The effect of graded doses of pentagastrin (2.7-6,000 ng/kg times h) on gastric acid secretion was measured in 20 duodenal ulcer (DU) and 20 non-DU subjects. Confirming many previous studies, the mean observed highest response and the mean calculated maximal response were significantly greater in DU than in non-DU subjects. The mean dose (plus or minus SE) in ng/kg times h for half maximal response, calculated from responses corrected for basal secretion and normalized for maximal secretion, was 92.1 plus or minus 1.7 in DU and 246.8 plus or minus 24.6 in non-DU subjects, a significant difference. By parallel line bioassay non-DU subjects required 2.8 times more pentagastrin (95% confidence limits 2.1-3.7) than DU highest response. Thus, this study shows that, compared with non-DU subjects, DU patients not only secrete more acid in response to stimulation by pentagastrin but also are more sensitive to stimulation by pentagastrin, that is, need smaller doses to achieve the same fraction of maximal response.