Humans as a source of N_2O - Evidences from breath air analysis and ~(15)N tracer experiments

摘要

GC analysis of exhaled air from randomly selected healthy adult volunteers without and with enteral nitrate treatment showed that its nitrous oxide concentration exceeded that of ambient air [0.34 ppm(v)] up to five times. It may be concluded that humans or probably warm-blooded animals in general represent a significant N_2O source. Investigations of selected healthy adults after enteral labelling with [~(15)N]arginine revealed that nitrous oxide formed in the human body is neither a by-product nor an intermediate of the endogenous NO synthesis from arginine. Probably N_2O is formed by reducing nitrate which may result endogenously from NO or has been taken up with food.