1.
Omeprazole, a substituted
benzimidazole inhibitor of the gastric H+/K(+)-
APT-ase, was administered orally at a dose of 20 mg in the morning of 3 consecutive days, followed by a period of 4 days without medication, and this intermittent dosage regimen was continued for 4 weeks. 2. During intermittent administration of
omeprazole to 10 patients with
duodenal ulcer disease and 10 healthy volunteers concentrations of serum
pepsinogen A and serum
pepsinogen C were monitored by sensitive and specific radioimmunoassays to study whether the effect of this treatment on serum
pepsinogens is different between patients and normal subjects and to evaluate whether serum
pepsinogen levels can be used to assess compliance with
therapy. 3. Administration of
omeprazole for 3 days induced significant increases in
pepsinogen A and
pepsinogen C serum concentrations, which rapidly fell after stopping the
omeprazole intake. The pattern of serum
pepsinogens after stopping the
drug was different for
duodenal ulcer patients and normal subjects. Both
pepsinogens were intra-individually related in both patients and healthy subjects when compared during the first and last 3-day course with
omeprazole, but in
duodenal ulcer patients both
pepsinogens tended to be higher in the last treatment course, while the opposite was found in the normal subjects. 4. The present study confirms that serum
pepsinogen concentrations are higher in
duodenal ulcer patients than in normal subjects, but also shows for the first time that serum
pepsinogens in the patients respond differently upon stimulation with
omeprazole.(ABSTRACT TRUNCATED AT 250 WORDS)