TY - JOUR T1 - Biotransformation of azapetine to oxazapetine in rat and rabbit liver fractions. JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 204 LP - 207 VL - 7 IS - 4 AU - P C Ruenitz AU - T P McLennon AU - L A Sternson Y1 - 1979/07/01 UR - http://dmd.aspetjournals.org/content/7/4/204.abstract N2 - The biotransformation of azapetine (I) to a lactam metabolite, oxazapetine (II), has been investigated in rat and rabbit hepatic subcellular fractions. In the presence of NADPH, II was produced from I in incubation mixtures containing 9000 g supernatant fraction or combined microsomes and cytosol, but not in mixtures containing microsomes or cytosol alone. Production of II was also observed when dehydrozapetine (III) was incubated with rabbit 9000 g supernatant fraction or cytosol. In washed rabbit microsomes II was not produced from III, but I was converted to III in the presence of NADPH. These results suggested that the biotransformation is initiated by microsomal enzymatic oxidation of I to III, followed by further oxidation of III to II by a soluble enzyme. ER -