Effects of ISC-4 on Phase I metabolism of NNK by A/J mice microsomes. A, metabolism of 3H[NNK] by liver microsomes at time points 0, 0.5, 2, 4, 8, 16, 24, and 72 h post ISC-4 administration (1.25 µmol in 100 µl corn oil IG). B, metabolism of 3H[NNK] by lung microsomes at time points 0, 4, 8, 12, 16, 24, and 72 h post ISC-4 administration (1.25 µmol in 100 µl corn oil IG). C, effect of in vitro incubation of ISC-4 on control liver microsome metabolism of NNK to keto acid. D, effect of in vitro incubation of ISC-4 on control liver microsome metabolism of NNK to keto alcohol.