title: Endogenous N-nitrosation in man assessed by measurement of apparent total N-nitroso compounds in faeces.
abstract: The faecal concentration of substances responding to the chemical test for N-nitroso compounds (apparent total N-nitroso compounds, ATNC) was investigated in human subjects consuming their normal free-choice diet. Concentrations ranged from 40 to 590 micrograms (N-NO)/kg faeces. To ascertain the likely relative contributions of endogenous ATNC formation and preformed, dietary ATNC, the subjects consumed a diet low in nitrate and ATNC for 8 days. At the end of this period, ATNC had decreased substantially with concentrations ranging from below the 40 micrograms (N-NO)/kg detection limit up to 143 micrograms (N-NO)/kg, mean 82 micrograms (N-NO)/kg. On supplementing this diet with 300 mg nitrate/day, faecal ATNC levels increased markedly. On the third day of this regime, values were in the range 73-714 micrograms (N-NO)/kg with a mean of 307 micrograms (N-NO)/kg. The results, together with the known limited occurrence of ATNC in the majority of foodstuffs so far tested, generally non-detectable or less than 100 micrograms (N-NO)/kg, suggest that endogenous formation via species derived from dietary nitrate is likely to be an important source of ATNC in human faeces.
authors.affiliation: BIBRA Carshalton, Surrey, UK.
authors.forename: I R
authors.initials: IR
authors.lastname: Rowland
authors.forename: T
authors.initials: T
authors.lastname: Granli
authors.forename: O C
authors.initials: OC
authors.lastname: Bøckman
authors.forename: P E
authors.initials: PE
authors.lastname: Key
authors.forename: R C
authors.initials: RC
authors.lastname: Massey
mesh_terms: D000328:Adult; D004032:Diet; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage / Q000378:metabolism; D015538:Nitrosation; D009603:Nitroso Compounds / Q000032:analysis / Q000378:metabolism* / Q000493:pharmacokinetics; D012737:Sex Factors
chemical_list: D009566:Nitrates; D009603:Nitroso Compounds