Figure 4. Iron homeostasis. (A) Plot of serum ferritin levels (ng/mL) versus date is shown. Serum Ferritin levels were initially quite high (normal values 24-336 ng/ml) but normalized after treatment was initiated, indicating a block in iron utilization during the hyperthyroid state. The vertical dotted line indicates the time of initiation of therapy for hyperthyroidism. (B) Iron levels (purple diamonds, mcg/dL) and iron saturation (red diamonds, %) were plotted versus date. The vertical dotted line indicates the time of initiation of therapy for hyperthyroidism. The data suggest that hyperthyroidism initiated a functional block in iron utilization that was alleviated following treatment; thus, iron level and iron saturation jumped up after methimazole was started.