Serum group I pepsinogen levels in patients with peptic ulcer and normal subjects.

Serum group I pepsinogen (PG I) levels were measured by radioimmunoassay in patients with peptic ulcer and normal subjects. The mean (+/-S.E.) serum PG I level in 318 normal subjects was 79 +/- 3 ng/ml. The level in males, 87 +/- 2 ng/ml (n = 246), was significantly higher than in females, 72 +/- 4 ng/ml (n = 72). The serum PG I levels in the patients with gastric ulcer and in those with duodenal ulcer were 91 +/- 7 ng/ml (n = 31) and 117 +/- 10 ng/ml (n = 31), respectively. Both values were significantly higher than the value in the subjects with endoscopically normal mucosa (63 +/- 5 ng/ml). No significant change in serum PG I was observed after subcutaneous injection of tetragastrin or after ingestion of meal. A significant correlation was found between serum PG I and stimulated pepsin output, peak pepsin output, and maximal acid output and peak acid output. These findings suggest that serum PG I may be determined by the chief cell mass.