Figure 7

Hepcidin analysis in urine under different conditions. A urine sample was diluted to 20 μg protein/ml and spiked with 200 ng/ml labelled hepcidin and 0–32% (v/v) human serum devoid of hepcidin (as estimated from SELDI spectra – see the top spectrum in Figure 4). Panel a: endogenous hepcidin peak intensity with/without TIC-normalisation plotted against laser power. Filled symbols denote mean (± SEM) non-normalised intensity of all 8 samples at each laser setting (not [serum] dependent). Open symbols denote mean (± SEM) TIC-normalised intensity of the 4 samples with 0–32% serum added (the TIC normalised is [serum] dependent). Panel b plots the TIC-normalised hepcidin intensity and the concentration calculated from the peak ratio over a range of serum concentrations (constant laser power).