Interaction of pargyline with rat hepatic microsomes.

When administered by intraperitoneal injection daily for 3, 7 or 14 days, pargyline (75 mg/kg) significantly reduced rat hepatic microsomal ethylmorphine N-demethylase activity and cytochrome P-450 content. Injection of a lower dose of pargyline (15 mg/kg) failed to alter significantly either ethylmorphine N-demethylase activity or cytochrome P-450 content. Studies performed in vitro reveal that pargyline is metabolized to at least three compounds by rat hepatic microsomes. Thin-layer chromatography and other analyses suggest that one metabolite is an N-demethylated form, norpargyline.