Fig. 5.

Copper loading increases iron release from J774 macrophages after erythrophagocytosis. J774 cells were treated with 50, 100, or 200 μM CuSO₄ or 200 μM Fe-NTA for 48 h before release assays. Cells were washed free of the metals, and ⁵⁹Fe-labeled, opsonized rat erythrocytes were added for 1.5 h at 37°C. After lysis of nonphagocytosed red blood cells, J774 cells were washed, resuspended in fresh culture media, and allowed to release iron into the media for 3 h. At the end of experiments, ⁵⁹Fe activities in the collected media and cell lysates were measured by γ-counting. Iron release was calculated as percentage of ⁵⁹Fe in the media versus total ⁵⁹Fe measured (media plus cells). Values shown are the mean percentage iron release ± SEM (n = 9). ^*, Treatments not sharing the same superscript are significantly different from each other (ANOVA followed by Tukey's highly significant difference test, P < 0.05).