N-nitroso compounds, nitrite and pH in human fasting gastric juice.

Total N-nitroso compounds, ethyl acetate-extractable N-nitroso compounds and nitrite were measured in 146 samples of fasting gastric juice to investigate their relationship with pH. A positive correlation was found between pH and extractable N-nitroso compounds (r = 0.206, P < 0.02), whereas total N-nitroso compounds were pH-independent. It was inferred that pre-cancerous conditions associated with high gastric pH may be produced by an increase in the extractable N-nitroso compounds, which constitute only a small fraction of the total gastric N-nitroso compounds.