Interaction between phencyclidine and its pyrolysis product, 1-phenylcyclohexene.

The interaction between phencyclidine (PCP) and its pyrolysis product, 1-phenylcyclohexene (PC), at metabolic level was evaluated in Swiss male mice (21-24 g). PC (1.1, 2.2 and 4.4 mmol/kg/day for 4 days, IP, in corn oil) treatment to mice induced the in vitro metabolism (p less than 0.05) of amidopyrine (17%), aniline (12%), phenacetin (62-100%), pentobarbital (20-26%), PCP (25-80%) and benzo[a]pyrene (81-147%) in the 9000 g liver fraction and the hepatic microsomal contents of cytochrome P-450 (18-42%). The induction of the mixed function oxygenase (MFO) system was consistent with the decreases in the concentrations of IP administered pentobarbital (0.27 mmol/kg, in saline) and PCP (16.4, 32.8 and 65.6 mumol/kg, in saline) in the serum, brain, liver and kidneys of PC pretreated mice. At 1 hr after the above doses of PC, the in vitro metabolism of amidopyrine, aniline, or phenacetin was not inhibited. However, the biotransformation of benzo[a]pyrene was inhibited by 33 to 45%. Though PC after a single dose did not alter the tissue concentrations of PCP, it increased the pentobarbital concentrations in the tissues studied (p less than 0.05). These results indicate that PC has a potential to induce the MFO system after the 4-day treatment. This property of PC plays an important role in the reduction of the action of PCP by enhancing its metabolism, thereby decreasing its tissue levels.