Microsomal N-hydroxylation of trans-4'-halo-4-acetamidostilbenes

Hamster liver microsomes catalyze the N-hydroxylation of trans-4-acetamidostilbene and its 4'-Cl and 4'-F analogs. Other metabolites which were detected and quantitated were the 4'-OH derivative of trans-4-acetamidostilbene and the glycolamides of the 4'-Cl and 4'-F compounds. The kinetics of metabolism of the acetamidostilbenes were also determined. The apparent KM values of N-hydroxylation of the four substrates were similar, but the maximal velocities showed marked variations. The Vmax for the 4'-Br analog was 16% of that of trans-4-acetamidostilbene, and the rate of N-hydroxylation of the 4'Cl and 4'-F analogs was only 3% of that of the parent compound.