MASS-SPECTROMETRIC IDENTIFICATION OF N-PHENYLLINOLEAMIDE METABOLITES IN MOUSE PERITONEAL-MACROPHAGES

N-Phenyllinoleamide (NPLA), the anilide of linoleic acid, has been reg arded as a marker of the case oils associated with toxic oil syndrome, but the mechanisms of toxic injury remain enigmatic. Experimental dat a have related an increased systemic toxic effect of heated linoleic a nilides to chemical structural modifications that might also be possib le by in vivo metabolism; however, little is known about their metabol ism. Taking into account that NPLA is a derivative of linoleic acid, a fatty acid that can be metabolized by lipoxygenase activity to a vast array of derivatives possessing biological activity, the objective ha s been to elucidate the oxidative metabolism of NPLA by mouse peritone al macrophages, a cellular model with high lipoxygenase activity. Cell s were incubated with 0.1 mM NPLA spiked with N-phenyl[1-C-14]linoleam ide. The metabolites were separated by high-performance liquid chromat ography and individually collected prior to GC/MS analysis. Identifica tion of trihydroxy-, monohydroxy- and epoxy-derivatives of NPLA, sugge sts that this xenobiotic can be metabolized via the same oxidative pro cesses as for linoleic acid. Furthermore, identification of the non-am idated monohydroxylated and trihydroxylated derivatives of linoleic ac id arising from NPLA suggests an amidase-like activity with release of aniline and the free fatty acid. These results provide information ab out possible biological structures arising from NPLA, and open the way evaluate the biological significance of these metabolites in the infl ammatory reactions associated with toxic oil syndrome.