Nitrosoproline formation in control and antibiotic-treated rats given nitrate and proline.

The role of the gastrointestinal microflora in the nitrate-dependent formation of nitrosoproline was assessed in control and antibiotic-treated rats. Urinary nitrosoproline excretion as an index of in vivo nitrosamine formation was shown to be unaffected by bacterial decontamination of the alimentary tract, and proceeded in the absence of detectable nitrate reductase activity in the intestinal contents. These observations suggest that the gut microflora are not required for the formation of nitrosamino acid from nitrate and proline.