Iron absorption post-absorptive excretion

As mentioned previously BjSrn-Rasmussen and Lykken both reported a relationship between post-absorptive excretion of iron and serum ferritin The higher the subject s serum ferritin the greater the body iron stores and the more post-absorptive excretion which was observed For uniformity we have defined FAE-9 as the percentage of the dose of isotope which was excreted more than 9 days after the dose Nine days comprise three 3-day stool collection periods Bjorn-Rasmussen used a 10-day cutoff point (29) ... 

Figure 6 Relationship between serum Iron and post-absorptive excretion (PAE-9) of iron.

Fost-ahsorptive excretion of zinc and copper has not previously been reported Presumably the same or similar mechanisms are involved in the excretion of iron, zinc, and copper, since the excretion of the three metals appears to be synchronous in most subjects Post- absorptive excretion of iron goes on for four to five weeks after an oral dose of (29). Using stable isotopes of Fe, Zn, and Cu, we have observed post-absorptive excretion of all three metals for up to six weeks after the isotope dose. 

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