Gas chromatographic determination of N-acetylisoputreanine-gamma-lactam, a unique catabolite of N1-acetylspermidine.

A capillary gas chromatographic method with nitrogen-phosphorus detection for the determination of N-acetylisoputreanine-gamma-lactam (acisoga) in urine is described. The method was validated by comparing the results with those given by an isotope dilution mass fragmentographic method. Making use of specific inhibitors for copper-dependent amine oxidase and polyamine oxidase in rats, it was demonstrated that acisoga is formed by oxidative deamination of N1-acetylspermidine by the former enzyme. Moreover, acisoga is not a substrate for pig liver polyamine oxidase. Increased concentrations of acisoga, relative to N1-acetylspermidine, in urines of patients with non-Hodgkin's lymphoma indicated that this conversion diminishes the sensitivity of N1-acetylspermidine as a marker for (tumour) cell death.