Metabolism of nitrous oxide.
Nitrous Oxide/N2O. Eger EI II., ed., New York: Elsevier, 1985 Jan; :203-210
Studies on the metabolism of nitrous-oxide (10102439) were conducted using nitrous-oxide labeled with the stable isotope nitrogen-15. Isotope ration mass spectrometry was used to quantify metabolically produced nitrogen-15. Animal studies indicated that nitrous-oxide was not apparently metabolized by either liver microsomes or liver homogenates. Even so, nitrous-oxide was metabolized through a reductive pathway by anaerobic bacteria from the human intestine. Nitrous-oxide also appeared to be an intermediate in the reduction of nitrite to nitrogen by bacteria. Incubations of nitrite and nitric-oxide molecules with bacteria produced nitrogen gas that contained a nitrogen atom from both nitrite and nitric-oxide molecules. For the reduction of nitrous-oxide to nitrogen, it may be necessary for a copper containing enzyme to be present. Otherwise, nitrous-oxide would accumulate. During the metabolic process free radicals were formed which could produce toxic agents such as peroxidized lipids. The toxicity of the free radicals was suggested by studies of an aqueous solution of nitrous-oxide that was irradiated by x-rays. The irradiated solution was lethal to Escherichia-coli. Experiments were designed to detect the free radicals produced during nitrous-oxide metabolism. While it appeared that nitrous-oxide radical formation could produce toxic effects, the known toxicity of nitrous-oxide could be ascribed to its inactivation of vitamin-B12.
NIOSH-Grant; Grants-other; Gastrointestinal-system; Metabolic-study; Nitrogen-compounds; Enzyme-activity
Anesthesia Stanford University Department of Anesthesia Stanford, Calif 94305
Other Occupational Concerns; Grants-other
Stanford University, Stanford, California