<p>The cells were transfected with HO-1 siRNA for 24 hours and then challenged with 100 μM heme for a further 24 hours. The cells were harvested by scraping and extracted with cold 10% perchloric acid. <b>(A)</b> Concentration of “loose” iron in the extract supernatants. <b>(B)</b> “Bound” intracellular iron concentrations. Note that in a nitric acid digest, “bound” iron includes not just ferritin bound iron but also heme iron. Data are means ± SEM of 3 independent experiments. *p≤0.01.</p
