Quantitation of reticuloendothelial iron kinetics in humans
Stefanelli, M.; Bentley, D.P.; Cavill, I.; Roeser, H.P.
American Journal of Physiology 247(5 Pt 2): R842-R849
1984
ISSN/ISBN: 0002-9513 PMID: 6496771 Document Number: 228107
Reticulendothelial iron kinetics were studied in a simultaneous dual-isotope study in 10 healthy adults in whom [55Fe]ferric hydroxide phosphate colloid was used to label the reticulendothelial Fe pools, and [59Fe]transferrin was used to define plasma Fe kinetics. The simultaneous clearance of 55Fe and 59Fe from plasma and the uptake of each into red blood cells were estimated for 14 days. The [55Fe]colloid was cleared almost immediately, and its Fe was rapidly released to bind to plasma transferrin. Red cell incorporation of 55Fe was much slower than that of 59Fe bound to transferrin in vitro. The results were analysed by a new model of reticuloendothelial Fe metabolism that contained 2 reticuloendothelial Fe pools; one had a rapid turnover and donated Fe to transferrin, and the other, a storage pool, had a slower turnover. The transit pool contained a mean of 164 mu mol Fe with little variation among subjects, whereas the storage pool was somewhat larger (mean 873 mu mol Fe) and showed more variation among subjects. In general an equal proportion of the Fe leaving the transit pool went to transferrin and to the storage pool. The distribution between the 2 routes did not seem to be related to plasma Fe concentration, latent Fe-binding capacity or transferrin saturation.