University of Utah Medical School researchers made a surprising discovery about the blood chemistry of brown trout in cold western rivers.  They found that these fish have multiple genes that result in different molecules (longer or shorter versions) of the iron-balancing hormone hepcidin.  Some forms of trout hepcidin function in iron-metabolism and others, in bacteria control, with differences responding to water temperature.   One expression of the fish molecule is identical to the sole human form, which acts in both functions, and has an identical binding domain for the iron-transporting receptor ferroportin.  These Utah “fishermen” then synthesized the hepcidin-binding domain (for ferroportin) on agrose beads and developed a quick, sensitive assay that determines hepcidin concentrations in human blood.  Too much hepcidin causes anemias; too little results in organ-damaging iron accumulations.  The prevalence rate for anemias in the US is 1 in 77 people (much greater than most inherited monogenic disorders), or an estimated total of 3.5 million.        MORE