Denitrosation of diphenylnitrosamine in vivo

A single dose of diphenylnitrosamine (NDphA) was applied orally or intraperitoneally (i.p.) to rats. The urine was sampled and analysed for nitrite/nitrate by ion chromatography and for diphenylamine (DphA) plus hydroxydiphenylamine by gas chromatography. The major metabolite was nitrate. Nitrite and DphA were found in minor amounts. In a somewhat higher concentration, a monohydroxylated DphA was detected. It is concluded that NDphA is denitrosated to nitric oxide (NO) and DphA in the organism and that NO is then converted into nitrite and nitrate.