Estimate of production of gaseous nitrogen in the human body based on 15N analysis of breath N2 after administration of [15N2]urea Dedicated to Professor Dr habil. Hans Faust on the occasion of his 85th birthday. [electronic resource]

• Published in: Isotopes in environmental and health studies Vol. 49; no. 4; pp. 454 - 463
• Main Author: Junghans, Peter
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.12.2013
• Subjects: endogenous molecular nitrogen; excretion; gas exchange; gas exchange measurement; Helicobacter pylori; Helicobacter pylori; humans; N breath test; nitrogen; nitrogen balance; nitrogen metabolism; nitrogen-15; nitrosation; oral administration; patients; stable isotope tracer technique; stable isotopes; urea
• ISSN: 1477-2639; 1025-6016; 1477-2639
• DOI: 10.1080/10256016.2013.828718

After oral administration of [ ¹⁵N ₂]urea (1.5 mmol, 95 atom% ¹⁵N), we found that breath N ₂ was significantly ¹⁵N-labelled. The result suggests that molecular nitrogen in breath must be partly produced endogenously. Based on a metabolic model, the endogenous N ₂ 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 N ₂ 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.