Formation of nitrite in gastric juice of patients with various gastric disorders after ingestion of a standard dose of nitrate--a possible risk factor in gastric carcinogenesis.
Samples of fasting gastric juice (12-h fasting period) from patients with various upper gastrointestinal complaints and from healthy controls were collected by aspiration immediately before and 30, 90, and 240 min after ingestion of 200 mg nitrate in water. Nitrite concentration in the gastric juice of healthy controls remained essentially in a low concentration range throughout the whole sampling period (median values at various time points, 0.1-1.7 mg/L). Patients with gastric and duodenal ulcers and patients who had undergone proximal-gastral vagotomy did not show significant increases in gastric nitrite at any time when compared with healthy controls, using the Wilcoxon rank sum test. Patients with chronic atrophic gastritis and those who had undergone Billroth I or Billroth II gastric resection, however, showed significant increases in gastric nitrite, sometimes with high individual peaks: 80 mg/L in one patient with chronic atrophic gastritis, 50 mg/L in a Billroth I patient and 200 mg/L in a Billroth II patient. The results show that patients with chronic atrophic gastritis and patients who have undergone Billroth I and Billroth II gastrotomy not only have higher basal nitrite values in their gastric juice (12-h fasting) but also react with significantly higher increases in gastric nitrite to an oral dose of 200 mg nitrate, compared with healthy controls, ulcer patients and patients who have undergone proximal-gastral vagotomy. Higher nitrite levels might lead to an enhanced intragastric formation of N-nitroso compounds, and this might be relevant to the increased gastric cancer risk of these groups of patients.