Fig. 1.

The specific activity of URO-D is reduced in cytosolic extracts of porphyric mouse liver. Both wild-type (gray bars) and Uro-d^+/− (black bars) mice were treated with iron dextran (Fe), drinking water supplemented with ALA, and a mixture of polychlorinated biphenyls (Aroclor 1254) and killed after 21 days, when porphyria was fully developed. (A) Western blotting of 30 μg of total cytosolic protein from each animal by using a 1:200 dilution of a polyclonal rabbit anti-human URO-D antiserum as a primary antibody and a 1:2,000 dilution of a horseradish-peroxidase-labeled goat anti-rabbit IgG as a secondary antibody. The blot was developed by using ECL reagents (Amersham Biosciences/GE Healthcare, Piscataway, NJ). URO-D protein in Uro-d^+/− animals was approximately half of the wild-type value. Protein content did not change when URO-D catalytic activity fell in animals of either genotype. (B) URO-D catalytic activity before and after treatment. Two animals of each genotype were analyzed per group. URO-D activity for each animal is aligned below the corresponding band on the Western blot.