Enzymatic activity of liver, kidney, and lung cytosol of ΔPMT mice toward DCNB and EPNP. (A) Activity of cytosolic preparations from the three tissues was determined spectrophotometrically. The genotype represented by each bar is indicated in the panel. (B) Activity of hepatic cytosol toward EPNP was determined spectrophotometrically. Values represent the mean of four animals ± S.E.M. *P < 0.05, **P < 0.01, ***P < 0.001, determined by unpaired t test.