D-AMPHETAMINE TOXICITY IN FRESHLY ISOLATED RAT HEPATOCYTES: A POSSIBLE ROLE OF CYP3A.

The aim of this study was to trace D-amphetamine toxicity in isolated rat hepatocytes and to elucidate a possible involvement of CYP3A in the mechanisms of its toxicity. To this end, male Wistar rats were treated with nifedipine (5 mg kg-1 i.p., 5 days), a substrate and inducer of CYP3A. Hepatocytes isolated from nifedipine-treated and control rats were incubated with D-amphetamine at a concentration of 100 µmol L-1, which was determined to be an average toxic concentration (TC50) for the compound. To evaluate the possible toxic effects of D-amphetamine on freshly isolated rat hepatocytes, we assessed the following parameters: cell viability, lactate dehydrogenase (LDH) activity, and glutathione (GSH). The results showed that nifedipine potentiated amphetamine cytotoxicity in vitro, as follows: cell viability dropped by 65 % (p<0.001), GSH by 80 % (p<0.001), and LDH activity increased by 190 % (p<0.001). To clarify the role of nifedipine in amphetamine cytotoxicity, we used amiodarone, a substrate and an inhibitor of CYP3A. Pre-incubation of nifedipine-treated hepatocytes with amiodarone (14 µmol L-1) significantly lowered amphetamine cytotoxicity. Our results confirmed the toxicity of D-amphetamine in isolated rat hepatocytes and the involvement of CYP3A in its metabolism and hepatotoxicity. [ABSTRACT FROM AUTHOR]