Effect of transferrin saturation on iron delivery in rats.

Studies were carried out in rats to evaluate the release of iron from monoferric and diferric transferrin. Isoelectric focusing was carried out on plasma tagged at low and high saturations, and it was shown that these represented primarily monoferric and diferric transferrin, respectively. In vivo studies with these tagged plasmas were carried out on normal, iron-deficient, and hypertransfused rats. In all three groups there was a greater in vivo uptake of iron from diferric transferrin by all tissues monitored. Though the amount varied in different animals, the ratio of uptake between diferric and monoferric transferrin iron varied between 1.56 and 2.10 in the erythron and between 2.38 and 2.65 in the liver. These studies indicate that changes in transferrin saturation, by changing the proportion of monoferric to diferric transferrin iron, changed the amount of iron released to tissues.