Effect of treatment duration on radioiron mobilization from cultured, iron-loaded heart cells. Five-day-old cultures were first incubated with 0.36 mmol/L ⁵⁹Fe-labeled ferric ammoniun citrate for 24 hours, washed, and then exposed for 0.25 to 24 hours to 0.3 mmol/L of DF or IRC011. (▪) DF; () IRC011.