Excretion of N-mononitrosopiperazine after low level exposure to piperazine in air: effects of dietary nitrate and ascorbate.
The secondary amine piperazine may be nitrosated in vivo, following oral intake or occupational exposure by inhalation. The suspected carcinogen N-mononitrosopiperazine could be formed in the human stomach, and in part excreted in the urine. In this study, 0.4 microgram N-mononitrosopiperazine, determined by gas chromatography-Thermal Energy Analysis, was observed in the urine in one of four volunteers, at an experimental exposure by inhalation of 0.3 mg piperazine/m3. The intake of spinach and beetroot caused an increased nitrosation of piperazine, and up to 1.7 microgram N-mononitrosopiperazine was excreted in the urine in the four individuals. This excretion indicates that about 5% of the absorbed piperazine dose was converted to N-mononitrosopiperazine. With the same nitrate-rich diet, but with the addition of citrus fruits and fresh vegetables, the highest excretion was 0.6 microgram N-mononitrosopiperazine. The excretion was significantly correlated with the ratio between the maximum level of nitrite in saliva and the ascorbate level in plasma. There was also a significant interindividual variation. N,N'-Dinitrosopiperazine was not found in any sample of urine.
Bellander
T
T
Department of Occupational Medicine, University Hospital, Lund, Sweden.
Osterdahl
B G
BG
Hagmar
L
L
D000280:Administration, Inhalation; D000328:Adult; D000393:Air Pollutants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000097:blood / Q000494:pharmacology*; D002273:Carcinogens / Q000378:metabolism*; D004032:Diet; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000032:analysis; D009602:Nitrosamines / Q000378:metabolism*; D000077489:Piperazine; D010879:Piperazines / Q000378:metabolism*; D012463:Saliva / Q000032:analysis
D000393:Air Pollutants; D002273:Carcinogens; D009566:Nitrates; D009573:Nitrites; D009602:Nitrosamines; D010879:Piperazines; D000077489:Piperazine; D001205:Ascorbic Acid; C014711:1-nitrosopiperazine