Estimate of production of gaseous nitrogen in the human body based on (15)N analysis of breath N2 after administration of [(15)N2]urea.
After oral administration of [(15)N2]urea (1.5 mmol, 95 atom% (15)N), we found that breath N2 was significantly (15)N-labelled. The result suggests that molecular nitrogen in breath must be partly produced endogenously. Based on a metabolic model, the endogenous N2 production was estimated to be 0.40±0.25 mmol kg(-1) d(-1) or 2.9±1.8 % of the total (urinary and faecal) N excretion in fasted healthy subjects (n=4). In patients infected with Helicobacter pylori (n=5), the endogenous N2 production was increased to 1.24±0.59 mmol kg(-1) d(-1) or 9.0±4.3 % of the total N excretion compared to the healthy controls (p<0.05). We conclude that N balance and gas exchange measurements may be affected by endogenously produced nitrogen, especially in metabolic situations with elevated nitrosation, for instance in oxidative and nitrosative stress-related diseases such as H. pylori infections.
a Leibniz Institute for Farm Animal Biology, Institute of Nutritional Physiology 'Oskar Kellner' , Dummerstorf , Germany.
Peter
P
Junghans
D000328:Adult; D000368:Aged; D001944:Breath Tests; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000493:pharmacokinetics; D014508:Urea / Q000493:pharmacokinetics*; D055815:Young Adult
D009587:Nitrogen Isotopes; D014508:Urea; D009584:Nitrogen