Effect of cimetidine on gastric juice N-nitrosamine concentration.
Total extractable N-nitroso compounds, pH, and nitrite levels were measured in, and microorganisms were cultured from, the fasting gastric juice of 140 patients taking the H2-receptor antagonist cimetidine and from 267 subjects, including 50 healthy volunteers, not taking cimetidine. Significantly higher mean N-nitrosamine concentrations and pH levels were demonstrated in the cimetidine-treated patients; N-nitrosamine concentration increased with pH. In 30 patients studied, cimetidine treatment significantly increased gastric pH and N-nitrosamine concentrations, while in 23 patients withdrawal of cimetidine treatment resulted in a significant reduction of pH but not of N-nitrosamine concentrations. The gastric juice nitrite level was often raised and nitrate-reducing bacteria cultured were similar to those associated with other causes of hypochlorhydria. These results demonstrate for the first time a relation between gastric juice N-nitrosamine concentration, pH, and cimetidine treatment, and the findings are discussed in relation to gastric cancer induction.
D000126:Achlorhydria / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D001419:Bacteria / Q000378:metabolism; D002927:Cimetidine / Q000494:pharmacology*; D004064:Digestive System / Q000382:microbiology; D004415:Dyspepsia / Q000188:drug therapy; D005215:Fasting; D005260:Female; D005750:Gastric Juice / Q000378:metabolism*; D006146:Guanidines / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009573:Nitrites / Q000032:analysis / Q000378:metabolism; D009602:Nitrosamines / Q000032:analysis / Q000378:metabolism*; D013268:Stimulation, Chemical
D006146:Guanidines; D009573:Nitrites; D009602:Nitrosamines; D002927:Cimetidine