The effect of repeated parenteral administration of
aluminum (Al) was investigated to determine if a relationship exists between the severity of
anemia and increase in hepatic
heme oxygenase activity. Female Swiss Webster mice were dosed for 11 d with 50 mg Al/kg, as Al
lactate, and
sodium lactate was given to control mice. On d 12, hematocrit,
hemoglobin, blood smears, hepatic
heme oxygenase activity, and
cytochrome P450 levels were assessed. Significant decreases in hematocrit (39.1 +/- 0.7 vs 43.1 +/- 0.3% in controls) and
hemoglobin (13.1 +/- 0.4 vs 14.2 +/- 0.2 g/dL in controls) were produced by Al administration. Blood smears from Al-treated mice consistently showed smaller, more irregular red cells.
Cytochrome P450 content was significantly decreased (0.443 +/- 0.043 vs 0.665 +/- 0.055 nmol/mg) whereas hepatic
heme oxygenase activity was significantly increased (2.75 +/- 0.34 vs 1.66 +/- 0.20 nmol/mg/h) in Al-treated animals. The production of mild
anemia by parenteral
aluminum correlated significantly with the increase in
heme oxygenase activity, which, although only 66% greater than in control, preceded a significant loss of
cytochrome P450. The increased
heme oxygenase activity, with subsequent increased destruction of
heme and/or
heme proteins is discussed as a possible mechanism for the microcytic,
hypochromic anemia associated with Al overload.