Iron Exchange between Transferrin and the Placenta in the Rat

Laurell, C.-B. and E. Morgan. Iron exchange between transferrin and the placenta in the rat. Acta physiol. scand. 1964. 62. 271–279. — The process of iron exchange between transferrin and the placenta was studied in vitro using 59Fe, rat serum or purified rat transferrin labelled with 131I and placental tissue. The yolk sac placenta bound more transferrin and took up iron more rapidly than did the allantoic placenta. The amount of transferrin bound increased rapidly for the first 15 minutes but thereafter showed little further increase: the amount bound increased as the transferrin concentration was increased but was unaffected by the degree of its saturation with iron. Iron uptake increased steadily during incubation, was greater when the iron concentration was increased, but was unaffected by increasing the transferrin concentration with a constant iron concentration. The release of iron from placenta was slower than that of transferrin and was less into a transferrin-free solution than into plasma. The intravenous injection of rat transferrin in amounts sufficient to approximately double the plasma concentration did not alter the subsequent transfer of 59Fe from maternal plasma to the fetuses. The results show that the mechanism of iron exchange between transferrin and rat placenta is very similar to that between transferrin and reticulocytes.