Hepa1c1c7 cells were exposed to AMD or DEA, and 24 h later, cytotoxicity was assessed by measuring LDH activity released into the culture medium (Figs. 8A and B). Both AMD and DEA caused concentration-dependent LDH release. Significant cytotoxicity was observed with AMD concentrations greater than 20 ug/ml and DEA concentrations greater than 7 ug/ml. Addition of TNF (3 ng/ml) did not cause cytotoxicity alone but significantly potentiated the cytotoxicity of AMD and DEA.