Intracellular iron distribution in J774 macrophages. Macrophages were treated as described in the legend to Fig 1 and then lysed in cytoplasmic lysis buffer containing protease inhibitors and the intracellular iron distribution determined as described in the Methods. Nitrite production was assayed in the culture medium by the Griess reaction. Results shown are representative of 5 separate experiments. Values are given as the mean ± SE of triplicate cultures. Versus control: ^aP < .05,^bP < .01, ^cP < .001; versus IFN/LPS: ^#P < .01, ^##P < .001.