Is the gastrin response to secretin provocation a function of antral G-cell mass? Results in the hypergastrinemia of acid hyposecretion.

Some patients with hypergastrinemic achlorhydria may have false-positive secretin provocation as an exaggeration of the normal gastrin response to secretin, presumably related to an increased, or more responsive, antral G-cell mass. To test this hypothesis, we reviewed our experience with secretin provocation in normogastrinemic subjects with presumed normal antral G-cell mass (normal--17, duodenal ulcer--13) and in patients with hypergastrinemia related to changes in antral G-cells (vagotomy--5, hypochlorhydria--7, achlorhydria--10). Basal serum gastrin (mean +/- SEM) was progressively higher for each group; normal (42 +/- 3 pg/ml), duodenal ulcer (53 +/- 4 pg/ml), vagotomy (226 +/- 54 pg/ml), hypochlorhydria (346 +/- 92 pg/ml), achlorhydria (844 +/- 100 pg/ml). On selective analysis of only those with gastrin rises, significant differences (p less than 0.05) in peak gastrin change were found between achlorhydria (93 +/- 21 pg/ml) compared with all other groups and between hypochlorhydria (40 +/- 12 pg/ml) versus normal (6 +/- 1 pg/ml). Linear regression in these responders showed a significant correlation (p less than 0.001) between basal gastrin and peak gastrin change after secretin. There were no false-positive secretin provocation tests, but four achlorhydric patients had gastrin rises greater than 100 pg/ml, whereas no patient in the other categories had rises above 90 pg/ml. Our results support the concept that patients with hypergastrinemic achlorhydria tend to have greater G-cell responsiveness to secretin provocation, which may account for the false-positive results in some such patients.