CYTOGENOTOXICITY OF N-ACETYL-S-(1 2-PHENYL-2-HYDROXYETHYL)-CYSTEINE (NAPEC) IN CULTURED HUMAN BLOOD-LYMPHOCYTES/

N-Acetyl-S-(1/2-phenyl-2-hydroxyethyl)-cysteine (NAPEC) is a cysteine conjugate derived from the glutathione conjugate of styrene oxide. The dose- and time-dependent effects of NAPEC on SCEs and cell kinetics w ere studied in cultured human blood lymphocyte in vitro. Different con centrations of NAPEC (0-1500 muM) were added into the lymphocyte cultu res. After 36 h of exposure, both the induction of SCEs and cell-cycle delay were increased with increasing concentrations of NAPEC. When th e lymphocyte cultures were exposed to 1000 muM NAPEC for 22, 36 and 72 h during a total of 72-h culture period, no significant differences i n the induction of SCEs or cell-cycle delay were noticed due to 3 expo sure times. These results suggest that NAPEC possesses the potential t o induce SCEs and to inhibit cell-cycle progression and such potential seems to be independent of duration of exposure to NAPEC.