Evaluation of the nitrosamine hypothesis of gastric carcinogenesis in man.

Patients who had undergone a Billroth II gastrectomy (PG) or had pernicious anaemia (PA) and healthy matched control subjects (MC) participated in 24-h studies in which bacteria, nitrite and N-nitroso compounds (NOC) were measured in gastric juice and N-nitrosoproline (NPRO) in urine. Consistent with the nitrosamine hypothesis, intragastric levels of bacteria and nitrite were positively related to intragastric pH, but, contrary to the hypothesis, NOC in gastric juice and NPRO in urine were negatively related to intragastric pH.